text:
How do you checkmate with a queen?
How do you checkmate with a King and Queen versus King?
Is there a method that is faster than other methods in terms of moves?
Is there a foolproof method if you are in time trouble?

Treat the queen like a rook, but watch out for stalemates.

I love this series of questions that you're creating, very informative and covers all the basics, Is there a fool proof method if you are in time trouble? is a  great question, btw I didn't know that you had a youtube channel :)

@Fischer Thanks! :) Yeah, it is important to cover the basics. Yep, I do have a channel, I get 5 views per video, everybody loves it! :)

@RauanSagit you need to change the title of your videos :) nobody will search for live g11 and you don't include description in your videos, there's no way to find  it while searching, call it ruy lopez or whatever you get many more views :)

@Fischer Good point. I should do some title editing and add some descriptions. Make it more search friendly! :)

Grave Danger in King and Queen vs lone King
It's important for the winning side to avoid this common pitfall in this basic endgame.

The winning side should avoid placing their queen on the c2, c7, f2 or f7 squares if the opponent's King is in the nearby corner, because this leads to stalemate.
Below, I include some other types of stalemates that are not as well known.

Basic Idea
The plan is to drive the king to one of the edge ranks or files.

After this is achieved, the checkmating positions are usually like this -

Rectangle Method
This method is the fastest and similar to the rectangle method involving checkmate with a rook. The trick is to confine the opponent's king in the smallest possible rectangle with the queen's first move (if not already confined or can be confined at a later move) and then bring the side's own king closer to the opponent's king.
In the position to the left below, White plays 1. Qc6 as the first move, making the rectangle smaller.

Once this has been achieved, White simply brings the King closer to the Black King to drive it into one of the edge ranks or files. The rook check trick discussed in the rectangle method for the rook applies here with the queen check.
  [FEN "8/8/8/4k3/8/8/8/K6Q w - - 0 1"]

  1. Qc6 Kf5 2. Kb2 Ke5 3. Kc3 Kf5 4. Kd4 Kf4 5. Qf6+ Kg4 6. Ke3 Kh5
  7. Qg7 Kh4 8. Kf4 Kh3 9. Qg3#

Knight's Square Method
This method is mainly for beginners. Normally, experienced players will do better to use the rectangle method even in time trouble. However, it may at times help to use a  combination of this and the rectangle method.
If you're a in time trouble, this a very fast (in terms of how quickly you can make the moves on the board without thinking much) and foolproof (stalemates are always to be watched out for) way to checkmate the opponent's king.
With this method, you can literally finish playing the move before the opponent's hand even reaches the clock (assuming you're not playing online).
Consider this position where the Black King is on e5.

The King can be checked by a White knight from each of the 8 squares d3, c4, c6, d7, f7, g6, g4 and f3. In the Knight's Square Method, the idea is to move the queen to one of these squares (preferably one away from your king to avoid collisions in time trouble!) and then simply "copy" the opposite king's move.
Thus, in the position below, White first moves the queen to a "knight-square" 1. Qc6!

After that, the White Queen can "copy" the Black King's moves and remain in the knight's square, except, I REPEAT!!, except when the king moves to the corner (a1, a8, h1, or h8). For example, king moves right one square, queen moves right one square; king moves diagonally up one square, queen moves diagonally up one square. Once the Black King is driven to one of edge ranks or files, White brings the King to deliver the checkmate. This is demonstrated below.
  [FEN "8/8/8/8/3k4/8/8/K6Q w - - 0 1"]

  1. Qc6 Ke5 (1... Kd3 2. Qc5 Kd2 3. Qc4 Ke3 4. Qd5 Kf4 5. Qe6 Kf3 6. Qe5 Kg4
  7. Qf6 Kg3 8. Qf5 Kg2 9. Qf4 Kg1 10. Qf3 Kh2 11. Qg4 Kh1 12. Kb2 Kh2 13. Kc2 Kh1
  14. Kd2 Kh2 15. Ke2 Kh1 16. Kf2 Kh2 17. Qg2#) 2. Qd7 Kf6 (2... Kf4 3. Qe6 Kf3
  4. Qe5 Kf2 5. Qe4 Kf1 6. Qe3 Kg2 7. Qf4 Kg1 8. Qf3 Kh2 9. Qg4 Kh1 10. Kb2 Kh2
  11. Kc2 Kh1 12. Kd2 Kh2 13. Ke2 Kh1 14. Kf2 Kh2 15. Qg2#) 3. Qe8 Kg5 (3... Kg7
  4. Qe6 Kf8 5. Qd7 Kg8 6. Kb2 Kf8 7. Kc3 Kg8 8. Kd4 Kf8 9. Ke5 Kg8 10. Kf6 Kf8
  11. Qf7#) 4. Qf7 Kg4 5. Qf6 Kg3 6. Qf5 Kg2 7. Qf4 Kg1 8. Qf3 Kh2 9. Qg4 Kh1 10.
  Kb2 Kh2 11. Kc2 Kh1 12. Kd2 Kh2 13. Ke2 Kh1 14. Kf2 Kh2 15. Qg2#

Sometimes, one's own King can get in the way of the Queen in this method, as shown below.
     [FEN "8/8/8/2k5/4K3/5Q2/8/8 w - - 0 1"]

     1. Qb3 Kd6 2. Qc4 Ke7 3. Qd5 Kf6

In such cases, the King can simply be moved away and the same method continues.
     [FEN "8/8/5k2/3Q4/4K3/8/8/8 w - - 0 4"]

     1. Kf4 Kg6 2. Qe5 Kh6 3. Qf5 Kg7 4. Qe6 Kh7 5. Qf6 Kg8 6. Qe7 Kh8
     7. Kg5 Kg8 8. Kg6 Kh8 9. Qg7# *

As mentioned before, the one pitfall to be avoided in this method is the stalemate that can occur when mistakenly occupying the knight's square when the king is in the corner.
     [FEN "8/8/8/4Q3/8/8/6k1/K7 w - - 0 9"]

     1. Qf4 Kh1 2. Qg3 $4 (2. Qg4 $1)

Good, comprehensive answer. My only gripe are the red crosses in the stalemate diagrams; I find them distracting. Why not crop the diagrams instead?

Thanks Ralph. I'll keep your suggestion in mind for future posts where there are too many diagrams.

Most beginners cannot resist giving check, and announcing it. Ofter a check just sends the King to a safer spot. Mating with the Queen is a good exercise, but you do need a plan. Which of the mating positions shown here do I want to achieve? Does this move get me closer to it? Does my Queen constrict the other Kings freedom? Does your King get closer to where it needs to be? After that, does this check drive him to a worse situation? Finally, as you get close, will it give stalemate instead? Play this out against a friend using a clock. Practice until both of you can do it in ten seconds.

The first diagram only covers half the "dangerous" potential stalemate squares.

Lol, this question is not as silly as it sounds as once I was in time trouble and ended up stalemating my opponent by accident! Most players resign when their opponent is up a queen so such blunders can happen if you occasionally come across a player who is stubborn enough to play till the end. Anyway, after that incident I went back to studying the Queen and King vs. King endgame to avoid such embarrassments in the future!
So, this is how you do it:
1) Remember that stalemates are more easy with Q & K so it is important to check for a possible stalemate before every move.
2) Use your queen to slowly try to corner the opponent king until he is confined to one of the edge row or columns of the board.
[FEN "8/8/8/k2K4/8/1Q6/8/8 w - - 0 1"]

3) Bring the king in to the position shown in the diagram below:
[FEN "8/2K5/8/k7/8/1Q6/8/8 w - - 0 1"]

Remember that the king has to be in this position to deliver the checkmate.
4) Slowly nudge the opponent king towards the corner.
[FEN "8/k1K5/8/1Q6/8/8/8/8 w - - 0 1"]

5) When the opponent king is in this position, deliver the checkmate!
[FEN "8/k1K5/8/Q7/8/8/8/8 w - - 0 1"]

For eg.:
[FEN "8/8/8/3k4/8/7K/8/5Q2 w - - 0 1"]

1. Qf4 Ke6 2. Kg4 Kd5 3. Kf5 Kc5 4. Qd2 Kc4 5. Ke5 Kb3 6. Qc1 Kb4 7. Qc2    Kb5 8. Qc3 Kb6 9. Qc4 Kb7 10. Qc5 Kb8 11. Qc6 Ka7 12. Qb5 Ka8 13. Kd6 Ka7 14. Kc7 Ka8 15. Qa5# *

I don't know about the 'faster than other methods' bit, but it works!

The simplest answer is to restrict the enemy king's movements by "walling off", not attacking, with the queen, move by move, driving it to the edge and then bringing up the king to help administer the mate.  You must remember to always leave the king at least one free square once it's in a corner to avoid stalemate.  This is basically the same method used with the rook and king, although the king and rook must be used together in that case to drive the king to the edge and finally into a corner for the mate. All this may sound confusing in the abstract, but if you try it I'm sure it will become clear quickly enough. I don't think trying to memorize a "formula" beyond what I've just suggested will be of any more benefit.


text:
How do you checkmate with the pair of bishops?
How do you checkmate with the pair of Bishops and King versus King?
Are there any stalemates to look out for?
What are the key ideas / positions / tricks to make it work?
Thanks!

This is covered pretty well in the Wikipedia article on checkmate, as well as in other chess books.  Do we want to duplicate that content here?

I think we can do better. I've seen better methods than the Seirawan example on Wikipedia.

@KyleJones Wikipedia is static content. Here, we have the chance to vote and discuss. I think that Chess SE should cover all the basic and be the "to go" resource for basic chess questions as well as advanced ones. Cheers.

I always like to explain this in a visual way.
Basic Idea: Keep the bishops together. They form a large net (restricted area) from which the opponent king cannot escape.

Step 1: Push Opponent's King To Edge Rank or File
Keeping the bishops together and using the king for support, make the restricted area smaller to push the opponent's king back to an edge rank or file.
     [FEN "8/8/8/3k4/8/8/8/K2BB3 w - - 0 1"]

    1. Bd2 Ke4 2. Be2 Kd5 3. Kb2 Ke4 4. Kc3 Kd5 5. Bd3 Ke5 6. Be3 Kd5
    7. Bd4 Kd6 8.Be4 Ke6 9. Kc4 Kd6 10. Bd5 Ke7 11. Be5 Kd7 12. Kc5 Ke7
    13. Kc6 Kf8 14. Bf6 Ke8 15. Be6 Kf8

1. Bd2 Ke4 2. Be2

2...Kd5 3. Kb2 Ke4 4. Kc3 Kd5 5. Bd3 Ke5 6. Be3

6...Kd5 7. Bd4 Kd6 8.Be4

8...Ke6 9. Kc4 Kd6 10. Bd5 Ke7 11. Be5

11...Kd7 12. Kc5 Ke7 13. Kc6 Kf8 14. Bf6 Ke8 15. Be6 Kf8 (note: I intentionally chose the 13...Kf8 line because that is more instructive. For the 13...Kd8 line, please see the sample mates provided at the end).

Step 1 Accomplished!
Step 2: Push the Opponent's King to a Corner
In the above position, we shall choose the h8 corner. The key is to keep the opponent's king on the back rank while slowly taking away squares from the other side.
The idea now is to move the king over to the right hand side via Kc6-d5-e5-f5-g6 to cover f7 and then move the bishop to d7 to cover e8, thereby pushing the opponent's king to the corner.

   [FEN "5k2/8/2K1BB2/8/8/8/8/8 w - - 0 16"]

   1. Kd5 Ke8 2. Ke5 Kf8 3. Kf5 Ke8 4. Kg6 Kf8 5. Bd7 Kg8

Now, we can take control over f8, thereby pushing the opponent's king to the corner.

   [FEN "6k1/3B4/5BK1/8/8/8/8/8 w - - 0 21"]

   1. Be7 Kh8

Step 2 Accomplished!
Step 3: Checkmate the Cornered King
Here, it is important to be careful to avoid a common stalemate that occurs in this position.

We observe that White has to make a waiting move in order to challenge the g8 square with check, so that then after Kh8, Bf6+ would be mate.

And now the mate is easy.
    [FEN "7k/3BB3/6K1/8/8/8/8/8 w - - 0 22"]

    1. Be8 Kg8 2. Bf7+ Kh8 3. Bf6#

Below, I have included other types of checkmates that can occur if Black play's differently. I've also included the fastest mate from the original position which starts with 1.Bc3!
    [FEN "8/8/8/3k4/8/8/8/K2BB3 w - - 0 1"]

    1. Bd2 (1. Bc3 Ke4 2. Kb2 Kd3 3. Bf3 Ke3 4. Bd5 Kd3 5. Be5 Kd2 (5... Ke3) 6.
    Bd4 Kd3 7. Bc5 Ke2 8. Kc2 Kf1 9. Kd3 Ke1 10. Bg2 Kd1 11. Bf2 Kc1 12. Kc3 Kd1
    13. Bf3+ Kc1 14. Be3+ Kb1 15. Kb3 Ka1 16. Bd1 Kb1 17. Bc2+ Ka1 18. Bd4#) 1...
    Ke4 2. Be2 Kd5 3. Kb2 Ke4 4. Kc3 Kd5 5. Bd3 Ke5 6. Be3 Kd5 7. Bd4 (7. Bf4 Kc5
    8. Be4 Kb5 9. Be3 Ka6 10. Kc4 Ka5 11. Bc6 (11. Bb7 Ka4 12. Bb6 Ka3 13. Kc3 Ka4
    14. Bc6+ Ka3 15. Bc5+ Ka2 16. Kc2 Ka1 17. Ba4 Ka2 18. Bb3+ Ka1 19. Bd4#) 11...
    Ka6 12. Bc5 Ka5 13. Kd5 Ka6 14. Kd6 Ka5 15. Kc7 Ka6 16. Bb4 Ka7 17. Bb5 Ka8 18.
    Ba5 Ka7 19. Bb6+ Ka8 20. Bc6#) 7... Kd6 8. Be4 Ke6 9. Kc4 Kd6 10. Bd5 Ke7 11.
    Be5 Kd7 12. Kc5 Ke7 13. Kc6 Kf8 (13... Kd8 14. Bd6 Ke8 15. Be6 Kd8 16. Bf7 Kc8
    17. Be7 Kb8 18. Kb6 Kc8 19. Be6+ Kb8 20. Bd6+ Ka8 21. Bd5#) (13... Ke8 14. Bd6
    Kd8 15. Bf7 Kc8 16. Be7 Kb8 17. Kb6 Kc8 18. Be6+ Kb8 19. Bd6+ Ka8 20. Bd5#) 14.
    Bf6 Ke8 15. Be6 Kf8 16. Kd5 Ke8 17. Ke5 Kf8 18. Kf5 Ke8 19. Kg6 Kf8 20. Bd7 Kg8
    21. Be7 Kh8 22. Be8 Kg8 23. Bf7+ Kh8 24. Bf6# *

The basic idea is to constrain the enemy king with the bishops working together on a pair of diagonals, just as with a rook you work with ranks and files to push the enemy king to the side of the board.
With two bishops you need to drive the king to one of the corners.
We'll first start with the ending moves to know where you want to go.

[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "Checkmate with two bishops"]
[Black "example"]
[Result "1-0"]
[SetUp "1"]
[FEN "3k4/8/1K6/1B6/1B6/8/8/8 w - - 0 0"]
[PlyCount "11"]

1. Bd6 Kc8 2. Be7 Kb8 3. Bd7 Ka8 4. Bh3 Kb8 5. Bd6+ Ka8 6. Bg2# 1-0

Here is a longer example using the bishops to block along diagonals to force the opponent to the side, then the corner.

[Event ""]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "Another two bishops checkmate"]
[Black "example"]
[Result "1-0"]
[SetUp "1"]
[FEN "8/8/8/4k3/8/8/8/2B1KB2 w - - 0 0"]
[PlyCount "39"]

1. Bd3 Kd5 2. Bb2 Kd6 3. Kd2 Kc5 4. Kc3
Kd5 5. Kb4 Kd6 6. Bc4 Kc6 7. Bd4 Kd6 8. Kb5 Ke7 9. Kc6 Kf8 10. Bf6 Ke8 11. Kd6
Kf8 12. Be6 Ke8 13. Ke5 Kf8 14. Kf5 Ke8 15. Kg6 Kf8 16. Bd7 Kg8 17. Bc3 Kf8 18.
Bb4+ Kg8 19. Be6+ Kh8 20. Bc3# 1-0

Note that 10. Kd7  would be stalemate. You want to keep your king two squares from the side till near the end.
The last few moves, it is good to check the king into the corner mate, so that you don't stalemate by accident.

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text:
Longest sequence of mutually forced moves
In this position, the black move 1. ... Qc3 results in two consecutive forced moves, Kxc3 and Ke7:
2rkr3/2p5/2q5/8/8/8/3KP3/3R4 b - - 0 1

1... Qc3 2. Kxc3 Ke7

What is the longest sequence of mutually forced moves that can be constructed on a standard chessboard?

Inspired by Ed Dean's now deleted answer, here is another "infinite loop.”
[FEN "8/6p1/1p3pPk/1P3Pp1/1Pp3p1/KpP3P1/1P6/8 - - - 0 0 "]

There we go! (And I deleted my answer, since it was flawed, as its infinite loop wasn't fully forced.)

Although technically, since neither side can possibly checkmate the other here, it's an immediate draw (just like stalemate). So there aren't any legal moves at all here, the game is over.

Yes. It's in Article 1 of the rules, even ( http://www.fide.com/fide/handbook.html?id=124&view=article ). Infinite loops aren't really compatible with the laws of chess.

@Remco To be fair, you can have infinite loops as long as both players play along, because the 50 moves rule only says may be drawn - technicality obviously.

No, this has nothing to do with the 50 moves rule. See rules 1.3 or 5.2.b in the rules (my link). Or even rule 9.6 -- the rules describe this situation three times! It's an immediate draw, no claims.

Since the longest sequence of legal moves from this position is 0, perhaps it should not be the accepted answer!

Assuming you allow promoted material (since you didn't say anything :-),
this (on Page 13 of the PDF) is the (unfortunately, extremely unknown) finite record since ages. It shows the record for the longest sequence of only 1 legal move for each side, with use of promoted material.
[Title "Karl Scherer, Feenshach 1980, Page 13"]
[FEN "BQ4R1/2Q5/3Q4/4Q1pp/5B1P/6QK/Rrrrrrrq/R4nk1 w - - 0 1"]

1. Qxh2+ Rxh2+ 2. Bxh2+ Rxh2+ 3. Qxh2+ Rxh2+ 4. Qxh2+ Rxh2+ 5. Qxh2+ Rxh2+ 6. Qxh2+ Rxh2+ 7. Rxh2 g4+ 8. Rxg4+ hxg4+ 9. Kxg4 Kxh2

Wow, that's quite a "machine".

To make that position reachable, black must previously have had the queen on h1 and just captured a white pawn, knight or rook on h2, which then starts the forced sequence.

Can we get attribution in the answer?

Well, Karl Scherer himself :-) See: "feenschach" 51, 07-09/1980, S. 424 for a dead wood source. (Props to "apf" from schachfeld.de!)

@Rewan: Not regularly, neither on MatPlus :P feenschach is a German periodical for fairy chess, anybody at MatPlus could provide you with a scan if needed ('xept me - I'm doing virtually only orthodox 2# and don't have it).

A simpler infinite-loop setting:
[FEN "1kb5/1p1p4/1P1P4/8/8/4p1p1/4P1P1/5BK1 w - - 0 1"]

One can [put white pawns on a7 and f3, put black pawns on c6 and h2, and move black's king to a8] to get 9 consecutive only-legal moves.  (without an immediate draw by dead reckoning; see Remco's comments to the other answer)

True, and then wBf1 and the e2/e3 pawns are not needed.

It would be the Bc8 and the d pawns that aren't needed, rather than the Bf1 and e pawns.

Sorry, you're right.

You mean like this?
[Title "Vilhelm Röpke, Skakbladet 1942, Mate In 6"]
[FEN "K1k5/P1Pp4/1p1P4/8/p7/P2P4/8/8 w - - 0 1"]

White mates in 6.
I guess that's 9 consecutive forced moves. It would be eleven except for black's choice of promotion piece on his fifth move. I don't know if it's a record, and I don't know who composed this classic chess problem.
P.S. Thanks to Rosie F. for sourcing the problem. Quoting Rosie F.'s comment:

This problem is by Vilhelm Röpke. PDB cites it as Skakbladet, 1942.

I'm not sure c1=Q can be considered forced, you had other promotions

@Alan That's why I said "I guess that's 9 consecutive forced moves. It would be eleven except for black's choice of promotion piece on his fifth move."

This problem is by Vilhelm Röpke. PDB cites it as Skakbladet, 1942.

@RosieF Thank you. I edited your comment into my answer.

There are two definitions of forced in play here:

Forced as in it the only legal move.

Forced as in you are bound by the rules of chess to make a move, i.e. your king is in check or it is your turn to move.

While there is some overlap between the two definitions, they are still separate categories in general. Here are records for each one, with and without promoted pieces.
Each record shall be recorded in length by plies, or half-moves, Since a player has a choice of what piece to promote to, promotion is not considered a fully forced move under definition #1.
One Legal Move, No Promoted Pieces-15 Ply
[Title "Bernd Schwarzkopf, Feenschach 1980 On Page 13"]
[FEN "8/2p5/2p5/1pP5/nP3p2/PP2B3/1pp1p3/brkbK3 b - - 0 1"]
[startflipped ""]

1... fxe3 2. bxa4 bxa4 3. b5 cxb5 4. c6 b4 5. axb4 a3 6. b5 a2 7. b6 cxb6 8. c7 b5

Source: The Die Schwalbe Chess Problem Database
Additional Source: A PDF of the original source
One Legal Move, Promoted Pieces-18 Moves
[Title "Karl Scherer, Feenshach 1980 On Page 13"]
[FEN "BQ4R1/2Q5/3Q4/4Q1pp/5B1P/6QK/Rrrrrrrq/R4nk1 w - - 0 1"]

1. Qxh2+ Rxh2+ 2. Bxh2+ Rxh2+ 3. Qxh2+ Rxh2+ 4. Qxh2+ Rxh2+ 5. Qxh2+ Rxh2+ 6. Qxh2+ Rxh2+ 7. Rxh2 g4+ 8. Rxg4+ hxg4+ 9. Kxg4

Source: The Die Schwalbe Chess Problem Database
Additional Source: A PDF of the original source
Multiple Legal Moves, No Promoted Pieces-12 Ply
[Title "Noam D. Elkies, Tim Krabbe’s Website Diary Entry #267 2004 (Version By Me)"]
[FEN "KBk5/P1P1p2p/2PN3P/P6p/2p3rP/2P3pB/6P1/8 b - - 0 1"]
[startflipped ""]

1... exd6 2. a6 d5 3. Bxg4+ hxg4 4. h5 d4 5. cxd4 c3 6. d5 c2 7. d6

Source: Diary Entry #267
Multiple Legal Moves, Promoted Pieces-22 Ply
[Title "Alexey Khanyan, Tim Krabbe's Website Diary Entry #267 2008, Mate In 11"]
[FEN "4Q2Q/4r3/4n1n1/1bbK1krn/RR1RR1RR/2qn1R1n/4n1nN/Q3Q3 b - - 0 1"]
[startflipped ""]

1... Ng2f4+ 2. Rfxf4+ N2xf4+ 3. Rgxf4+ Nh3xf4+ 4. Rhxf4+ Ndxf4+ 5. Rxf4+ Nhxf4+ 6. Rxf4+ Ngxf4+ 7. Rxf4+ Nxf4+ 8. Rxf4+ Kxf4+ 9. Qee5+ Qxe5+ 10. Qaxe5+ Rgxe5+ 11. Qxe5+ Rxe5+ 12. Qxe5#

Source: Diary Entry #267

Here are records if you want each one to end in checkmate.
One Legal Move, No Promoted Pieces-11 Ply
[Title "@Peter, Chess Stack Exchange 3/11/2015, Mate In 6"]
[FEN "7k/q5Q1/p4PPK/6PP/8/5P2/8/8 b - - 0 1"]
[startflipped ""]

1... Qxg7+ 2. fxg7+ Kg8 3. f4 a5 4. f5 a4 5. f6 a3 6. f7#

Source: This CSE question.
One Legal Move, Promoted Pieces-16 Ply
[Title "Bernd Schwarzkopf After Karl Scherer, Feenschach 1980 On Page 13, Mate In 8"]
[FEN "1KN4r/QRRRRRRr/kq6/p1q1R3/PP1q1b2/4q3/5q2/1r4q1 b KQkq - 0 1"]
[startflipped ""]

1... Qxa7+ 2. Rxa7+ Qxa7+ 3. Rxa7+ Qxa7+ 4. Rxa7+ Qxa7+ 5. Rxa7+ Qxa7+ 6. Rxa7+ Qxa7+ 7. Rxa7+ Rxa7 8. b5+ Rxb5+ 9. axb5#

Source: The Die Schwalbe Chess Problem Database
Additional Source: A PDF of the original source
Multiple Legal Moves, No Promoted Pieces-14 Ply
[Title "Noam D. Elkies, Tim Krabbe’s Website Diary Entry #267 2004 (Version By Me)"]
[FEN "KBk5/P1P1p2p/2PN3P/P6p/2p3rP/2P3pB/6P1/8 b - - 0 1"]
[startflipped ""]

1... exd6 2. a6 d5 3. Bxg4+ hxg4 4. h5 d4 5. cxd4 c3 6. d5 c2 7. d6 c1=Q 8. d7#

Multiple Legal Moves, Promoted Pieces-See the above Alexey Khanyan problem.

My understanding of a forced move is that the player doesn't have a choice.

I am still not sure what you mean, but I am certain this is not the usual definition of a forced move in chess.

After your edit, I am happy to see many nice examples in your answer but I failed to understand the difference between your "one legal move" and "multiple legal moves" sections. In both cases, each player has only one legal move at each turn ?

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text:
How do you win with a queen against a rook?
It is considered that a Queen and King beats a Rook and King. Yet, the technique can be tricky. How is it done the best way?

This question seems to be a duplicate: http://chess.stackexchange.com/q/883/167

@EdDean I like the answer (newshutz) better. It is a duplicate yet I think my formulation of the question is more clear and will lead to better search engine hits. Cheers.

I agree. I have merged the questions together, which added newshutz's answer to the old one. The old question can now be edited and re-titled as you suggest (which I also agree would be a good thing).


text:
How do you hold a draw with a bishop against a rook?
Bishop and King versus Rook and King is a draw. Yet it is easy to go wrong and lose. How do you hold a draw?

INTRODUCTORY NOTE:
Examples and instructions are taken from the book:
Y.Averbakh - Comprehensive Chess Endings Volume 2.
RELEVANT POSITIONS FOR PLAYING THIS ENDGAME SUCCESSFULLY:
I will quote the introduction from the above book:
"It is impossible to win against correct defense, even if the defender's king is driven back to the edge of the board. When retreating under the pressure of the opposing pieces, all he must do is to reach the corner of the opposite color to the bishop. We will call this the safe corner".
[Title "Weaker side holds balance"]
[fen "7k/R7/7K/8/8/1b6/8/8 w - - 0 1"]

1.Ra8+ Bg8=

White can't improve his position, since moving his king or moving rook along the 8th row will lead to stalemate. Black maintains balance by keeping his bishop on a2-g8 diagonal.
Again, quoting the same resource:
"If the defender's king is in a corner of the same color as his bishop, a win is normally possible. We will correspondingly call this the dangerous corner."
The following position demonstrates winning method when weaker side has king in "the dangerous corner":
[Title "Horwitz & Kling, 1851"]
[StartFlipped "0"]
[fen "6k1/5R2/6K1/8/3b4/8/8/8 b - - 0 1"]

1...Bg1! ( 1...Bc5 2.Rc7 Bf8 3.Rc8+-) 2.Rf1 Bh2! 3.Rf2 Bg3 4.Rg2! Be5 ( 4...Bh4 5.Kh5++- ) ( 4...Bd6 5.Rd2 Be7 6.Rc2!+- ) 5.Re2 Bd6 6.Re8+ Bf8 7.Rd8+-

Black must hide his bishop as in the main line, and we saw how to flush it out and win. The sub-variation shows what happens when he refuses to do so.
Here is another important position, where the result depends on who's turn to move is:
[Title "Horwitz & Kling, 1851"]
[fen "5k2/6R1/5K2/8/8/5b2/8/8 w - - 0 1"]

With the kings in opposition mating threats are in the air and if White moves first he is able to win. For the moment bishop is hiding behind the opposing king, but with the above rook maneuver White can flush it out:
[Title "Horwitz & Kling, 1851"]
[fen "5k2/6R1/5K2/8/8/5b2/8/8 w - - 0 1"]

1.Rg3 Be4 ( 1...Bh5 2.Rh3 Bf7 3.Rh8+ Bg8 4.Kg6+- ) ( 1...Bc6 2.Rc3 Bd7 3.Rb3! Kg8 4.Rb8+ Kh7 5.Rb7+- ) 2.Re3 Bg2 3.Re2! Bf3 4.Rf2+-

But if it is Blacks turn to move he saves the game by running with his king:
[Title "Horwitz & Kling, 1851"]
[StartFlipped "0"]
[fen "5k2/6R1/5K2/8/8/5b2/8/8 b - - 0 1"]

1...Ke8! 2.Ke6 Kd8 3.Kd6 Kc8=

Since the c6 square is inaccessible to the White king he is unable to make any mate threats.
These are the basic positions required to know in order to play this endgame well.
In the above book were provided studies which were complex, but can be solved with the knowledge of the above covered positions.
To keep this post clear, concise and useful I will omit them.
Best regards.

Nice answer. Just a note, there's a typo in your second move list, 6. Be8+ should be 6. Re8+.

@TKR: Fixed the typo. Thank you for your compliments. I hope this will help someone. Best regards. :)

I was already enthusiastic about the "nice diagrams", it is very nice to see now that you can also show multiple lines. Excellent use of these I'd say and a nice reference on top of that. I like it a lot :) (+1).

@JacobAkkerboom: Thank you so much. Hopefully this answer will help many in defending/winning these positions. It certainly was a great learning experience for me! Best regards.

First answer, I am hoping that there will be better answers with nice diagrams
Your goal should (could) be to get your king to a corner that is not the colour of your bishop. Your friend stalemate welcomes you there. White can chase you out of the corner, but not without letting you escape to center and eventually into the corner opposite the original corner. Of course if you enter the ending in awkward manner, for example with your king on the edge of the board, some other tactics/strategy may save your life.
This site explains the defence in the corner quite well.
Elsewhere on the same site there is also a tactic for the party with the rook to win if you are near the wrong corner. If you are on the edge of the board, but not near a corner, I think there are cases where you have to play very carefully/accurately.

There is also a good part on the Queen vs Rook endgame. You could post it as an answer to this question.

Also, for making "nice diagrams" see this question.

Forgot to say thanks for the site. It has some very useful stuff. +1 from me. Best regards.


text:
How do you hold a draw with a knight against a rook?
Knight and King versus Rook and King is a theoretical draw. Yet, you might lose if you don't know the method. How do you hold a draw?

I wish I could upvote this twice. This is such an important question.

The weaker side needs to keep Knight close to his King in order to achieve draw.
There are some special cases where the stronger side wins even in those situations, like when Knight is cornered or pinned in such a way that puts weaker side in zugzwang.
If the Knight is far away from the King then the result of the game depends whether or not the defending side is able to connect his pieces.
Here are some demonstrations:
Typical example:
[Title "Rook vs Knight, typical drawing plan"]
[fen "3nk3/2R5/8/4K3/8/8/8/8 w - - 0 1"]

1.Kd6 Nf7+! ( 1...Kf8?? 2.Rc8 Ke8 3.Ra8+- ) 2.Ke6 Nd8+ 3.Kf6 Kf8 4.Rd7 Ke8 ( 4...Nc6?? 5.Rd6+- ) 5.Re7+ Kf8 6.Re1 Nb7 7.Ke6 Ke8 8.Rb1 Nd8+ 9.Kd6 Nf7+ 10.Ke6 Nd8+ 1/2-1/2

It is useful to mention that in these position the defender should not allow vertical opposition( e6-e8 in the above example ), but should strive for the diagonal one( e8-f6 or e8/d6 ).
Even in the following position, Black is able to maintain a draw:
[Title "Drawing plan in a difficult position"]
[fen "5nk1/4R3/8/6K1/8/8/8/8 w - - 0 1"]

1.Kf6 Nh7+! 2.Kg6 Nf8+ 3.Kh6 Kh8 4.Rf7 Kg8 5.Rg7+ Kh8 6.Rg1 Nd7! ( 6...Nh7?? 7.Kg6! Kg8 8.Rg2 Nf8+ 9.Kf6+ Kh8 10.Kf7 Nh7 11.Rg8#) ( 6...Ne6 7.Kg6! Nf8 ( 7...Kg8 8.Kf6+! ) 8.Kf7 Nh7 9.Rg8# ) 7.Kg6 Kg8 8.Rd1 Nf8+ 9.Kf6 Nh7+ 10.Kg6 Nf8+ 1/2-1/2

Winning motifs for the stronger side:
We already saw one above-the decisive pinning of the knight that leads to zugzwang:
[Title "Decisive zugzwang"]
[fen "R2nk3/8/3K4/8/8/8/8/8 w - - 0 1 "]

1.Rc8 Kf7 2.Rxd8+-

These motifs happen due to bad positioning of the King:
[Title "Defenders pieces are badly positioned : Cornered King"]
[fen "6nk/5R2/8/7K/8/8/8/8 w - - 0 1 "]

1.Kg6+- ( 1.Kg5+- )

or badly posted Knight:
[Title "Defenders pieces are badly positioned : Knight is away from his King"]
[fen "5k2/3R4/2n2K2/8/8/8/8/8 w - - 0 1"]

1.Rd6 Ne7 2.Rd8# 1-0

Another important motif is cornering the Knight :
[Title "Cornered Knight"]
[fen "6k1/5n2/6K1/8/8/3R4/8/8 w - - 0 1 "]

1.Rd5! Nh8+ 2.Kf6 Nf7 3.Rd7 Nh6 ( 3...Nh8 4.Ra7+- ) 4.Kg6+-

Sometimes defenders units are not badly placed but just separated. In that case stronger side can win if it can push Knight away from the king since then it will be able to trap it. Here is an example:
[Title "Knight is too far from his King"]
[fen "8/8/8/2k1K3/8/3R4/4n3/8 w - - 0 1 "]

1.Re3! Ng1 2.Kf5! ( 2.Kf4? Kd4! 3.Re1 Nh3+ 4.Kg3 Ng5 5.Kf4 Nh3+= ) 2...Kd4 3.Kf4 Kc4 4.Kg3 Kd4 5.Re1+-

SUMMARY:
The defender must keep his pieces together and avoid being cornered. Maintaining diagonal opposition with kings is desired.
The stronger side has several winning motifs:

Corner the opposing King and then execute double attack with the rook which threatens mate and attacks the Knight.
Corner the Knight and create zugzwang.
Push away the Knight as far away as possible from his King and then trap him.
In some special cases, exploit bad piece coordination to create decisive zugzwang.

NOTE:
Examples and instructions are taken from the book:
Y.Averbakh - Comprehensive Chess Endings Volume 2.
Best regards.

Very useful answer.

In analyzing and studying this endgame, I believe I have found a very simple way to explain the defensive technique (for this example, we will consider the defender to be Black). Once I learned this technique, I played some blitz Rook vs Knight endgames vs top chess programs and drew all of them.
Knight's Box
I found it useful to visualize the technique in term's of a box. Consider the knight on d1 (below). The knight can be visualized in a vertical box either to its left or right as shown. Note that the box is always vertical to the base of the knight.

In my analysis and study, I found that if Black can place its own king in the knight's box, and keep the opponent's king out of the box, then Black can hold the draw.

Note that the knight's box only works on a non-corner box. Thus, the green boxes below work, whereas the red ones don't.

Another exception is when the knight is pinned by the rook and the opponent king also attacks it at the same time, or when the opponent king attacks the knight and also checks the king with the rook.

Here is a sample blitz game I played against an engine that demonstrates this technique.
    [FEN "2R5/8/8/8/8/1K6/1n6/1k6 w - - 0 1"]
    [White "Engine"]
    [Black "Wes"]

    1. Rb8 Nd1 2. Re8  Kc1  3. Re2 Kb1  4. Kc4  Kc1  5. Kd3 Nb2+  6. Kc3  Nd1+
    7. Kc4  Nb2+  8. Kd4  Nd1  9. Rh2  Nb2  10. Kc3  Nd1+  11. Kb4  Nb2
    12. Re2  Nd1  13. Ra2  Kb1  14. Kb3  Kc1  15. Rc2+  Kb1 16. Rd2  Kc1
    17. Rh2  Kb1  18. Kc4 Kc1  19. Kd3  Nb2+ 20. Kd4  Nd1  21. Ke4  Nb2
    22. Ke3  Nd1+  23. Kf4 Nb2  24. Ke4  Nd1  25. Rg2  Nb2  26. Kd4  Nd1
    27. Kd3  Nb2+  28. Ke4  Nd1  29. Kd4  Nb2  30. Ke3  Nd1+  31. Kf4  Nb2
    32. Kf3  Nd1  33. Rh2  Nb2  34. Kf4  Nd1 35. Ke5  Nb2  36. Re2 Nd1
    37. Kd4  Nb2  38. Kd5  Nd1 39. Kc5  Nb2  40. Rh2  Nd1  41. Ra2  Nb2
    42. Kb4  Nd1 43. Re2  Nb2  44. Kb3  Nd1 45. Ra2  Ne3  46. Kc3 Nd1+
    47. Kd4  Nb2  48. Ke3  Nd1+  49. Kd3  Nb2+ 50. Rxb2  Kxb2 1/2-1/2

Not ALWAYS close to the King!
Although it generally helps to keep the king and knight together, it should be noted that there are some tricky positions where it is not desirable to keep the knight and the king together. This usually happens when the knight is on the b2, b7, g2 or g7 squares as shown below.
   [FEN "2R5/8/8/8/8/1K6/1n6/1k6 w - - 0 1"]

This is an important position in Rook vs Knight endgames. Here, after White plays 1. Kc3, the move 1...Nd1, which keeps the knight somewhat close to the king, loses. Instead, 1...Na4+ draws.
   [FEN "2R5/8/8/8/8/1K6/1n6/1k6 w - - 0 1"]

   1. Kc3 (1. Rc7 Nd1 2. Re7 Kc1) 1... Na4+ (1... Nd1+ $4 2. Kb3 Nb2 3. Kc3 Nd1+
   4. Kd2 Nb2 5. Ra8 Nc4+ 6. Kc3 Nd6 7. Ra4 Nb5+ 8. Kb3 Kc1 9. Rc4+ Kd2 10. Kb4
   Na7) 2. Kb4 (2. Kb3 Nb2 3. Rd8 Kc1!) Nb2 3. Kb3 Nd1 4. Rc7

Here, we reach another critical position, where keeping the knight close to the king loses -
   [FEN "2R5/8/8/8/8/1K6/8/1k1n4 w - - 0 1"]

   1. Rc7 Nf2 $3 (1...Nb2 $4 2. Rd7 Kc1 3. Rc7+ Kb1 4. Kc3 Na4+ 5. Kc4 Nb2+
   6. Kd4 Nd1 7. Kd3 Nb2+ 8. Kd2 Ka2 9. Kc3 Nd1+ 10. Kc2 Ne3+ 11. Kd2 Ng4
   12. Kc3 Ne3 13. Rd7 Kb1 14. Rd3 Nf5 15. Rd1+ Ka2 16. Re1 Nd6 17. Re5 Kb1
   18. Kb3 Kc1 19. Rc5+ Kb1 20. Rd5 Kc1 21. Rxd6) 2. Re7 Nd1 3. Rd7 (3. Re1 Kc1)
   3... Kc1 (3... Nf2 4. Rd2 Ne4 5. Rd1#) 4. Rd8 Nb2 (4... Nf2) 5. Rc8+ Kb1
   6. Kc3 Na4+ 7. Kb4 Nb2 8. Kb3 Nd1 1/2-1/2

Nice method! (+1) A funny bug: in your first game example, try holding down the "right-arrow" on your keyboard to fast-play the moves and hold it down until the move marker reaches the last move and release the key. Cheers.

@RauanSagit lol! Ya, I saw the king dance!

low priority but you could add ( 1... Kf8? 2. Rf5 ) on Cornered Knight on your next edit, "you could" not to be confused with "could you" I don't like making requests only suggestions :)


text:
What should you do after blundering during a game?
Let's say you are playing a game. Then suddenly, you make a bad move and e.g. blunder material. How should you react afterwards? What mind-set should you have? Can you even benefit from the blunder?

Related (or even duplicate?) http://chess.stackexchange.com/questions/1611/how-to-recover-from-a-blunder

React like this - http://www.youtube.com/watch?v=kZqcT66Fkzw and then recollect yourself to play a fighting game. :)

After a blunder, it helps to look objectively at the position once again and forget the history. You might have been better or worse; but that doesn't matter now after the blunder. What matters is how you go from here.
There could be many possibilities of salvaging a draw or even snatching a win by making the position very complicated and causing your opponent to blunder (I sometimes jokingly call this a "counter-blunder"). The least you want to ensure is to not make it psychologically easy for your opponent to win after your blunder. Make it difficult for the opponent. Play good moves. Do not be gloomy lest you blunder again.
Yes, there are times when you can even benefit from a blunder. A blunder may often give a player a kind of "license to thrill"! Now that you've blundered and your game is lost, you've got nothing more to lose! So why not embark on a nice sacrificial attack on the opponent's king (for example) and see if the opponent cracks under pressure? (A friend of mine actually tried this after blundering a piece and he won the game. Too bad I don't have the game).

Excellent points by Wes. I'd just like to add that, like with after any move, it's a good idea to look at the board as if you just came to the position in a puzzle. We often get so caught up in our plan that we miss better strategies that pop-up, or we don't see an opponents win.
If we try to take a fresh look at the board after every move we're likely to spot these things. This is more important after a blunder. Rather than focusing on the loss/mistake we should be looking for the best move on the current board.
It's also worth mentioning that a blunder, even a big one, doesn't always lead to a loss unless at really high level play. I'm currently rated around Elo 1,400 and I can't count the number of games where either me or my opponent have made a blunder but then gone on to win the game (usually through a similar blunder from the opposing player).

Excellent point-> "Trying to look at positions from a fresh angle "..

I'd say play like the computers do, i.e. just look for the best move in the ensuing positions and continue to play tough.  A little aggression wouldn't hurt either, as another respondent has indicated. Put the pressure on and give your opponent the chance to blunder in turn.  It's happened.  Don't by any means just trade away pieces into a losing ending, which I've also seen happen.

The advice given is pertinent but I prefer to spend time in futile regret, berating myself for the oversight, and wallowing in self-pity. I suppose it's not constructive but explains why I'm not world champ.


text:
Did Aronian make a mistake in the opening against Anand in round 1 of the FIDE Candidates 2014?
Here is the game
[Event "FIDE Candidates 2014"]
[Site "Khanty-Mansiysk RUS"]
[Date "2014.03.13"]
[Round "1.3"]
[White "Anand, Viswanathan"]
[Black "Aronian, Levon"]
[Result "1-0"]
[WhiteElo "2770"]
[BlackElo "2830"]
[ECO "C88"]
[Opening "Ruy Lopez"]
[Variation "closed, 7...O-O"]
[EventDate "2014.03.13"]
[FEN ""]

1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 Nf6 5. O-O Be7 6. Re1 b5 7. Bb3 O-O 8. h3 Bb7 9. d3 d5 10. exd5 Nxd5 11. Nbd2 Qd7 12. Nxe5 Nxe5 13. Rxe5 Nf6 14. Re1 Rae8 15. Nf3 Bd6 16. Be3 Re7 17. d4 Rfe8 18. c3 h6 19. Ne5 Bxe5 20. dxe5 Rxe5 21. Qxd7 Nxd7 22. Red1 Nf6 23. c4 c6 24. Rac1 R5e7 25. a4 bxc4 26. Bxc4 Nd5 27. Bc5 Re4 28. f3 R4e5 29. Kf2 Bc8 30. Bf1 R5e6 31. Rd3 Nf4 32. Rb3 Rd8 33. Be3 Nd5 34. Bd2 Nf6 35. Ba5 Rde8 36. Rb6 Re5 37. Bc3 Nd5 38. Bxe5 Nxb6 39. Bd4 Nxa4 40. Rxc6 Rd8 41. Rc4 Bd7 42. b3 Bb5 43. Rb4 Nb2 44. Bxb5 axb5 45. Ke3 Re8+ 46. Kd2 Rd8 47. Kc3 1-0

So I am wondering. The Spanish Marshall should give black plenty of compensation for the sacrificed pawn. Yet, black did not seem to get much play after white grabbed the pawn. Did black make a mistake in the opening or later in the middlegame (endgame)? Thanks!

Related: http://en.chessbase.com/post/providing-anand-for-anand-fans

Aronian played two sub-optimal moves in the middlegame - 16...Re7 and 18...h6. At each of these moves, the better move as per analysis by Houdini (depth 25 and above) was Nd5! (Houdini even prefers 17...Nd5, but 17...Rfe8 is not bad)
So his "mistake" was missing the opportunity to play Nd5, and instead playing 16...Re7 (which seems to be the major culprit) and 18...h6. If, instead, he had used the Nd5 idea, he could have equalized on move 16, and might have had better chances for equality if he had used it on move 18.
   [FEN "4rrk1/1bpq1ppp/p2b1n2/1p6/8/1B1P1N1P/PPP2PP1/R1BQR1K1 w - - 0 16"]

   1. Be3 Re7? (1... Nd5! 2. Bd2 c5=) 2. d4 Rfe8 (2... Nd5!? 3. Bd2 Nf4 4. Bxf4 Bxf4
   5.  a4+=) 3. c3 h6?! (3... Nd5! 4. Bd2 Rxe1+ 5. Nxe1 Nb6 6. Nc2+=) 4. Ne5! Bxe5
   5. dxe5 Rxe5 6. Qxd7 Nxd7 7. Red1+=

Explanation for 16...Nd5!
The idea behind 16. Be3 was to play 17. d4, which would strengthen White's position and prepare the Ne5 idea. Note that White couldn't play 16. d4 because of 16...Bxf3! The Ne5 idea gives White a pleasant edge in the endgame because of the two bishops. Therefore Black should have prevented it by preventing White's d4 move. Thus, the move c5 comes to mind, which discourages d4 because of c4, trapping the bishop on b3. However, c5 can wait for Nd5, an intermediate move, which forces White to retreat the bishop and also improves the position of the knight. After, Nd5 and c5, Black is completely equal.

According to Anish Giri in New in Chess 2014/3, 13...Nf6 was a dubious move. Black should have played 13... Nf4! 14. Nf3 Nxg2! 15. Kxg2 a5!! with a dangerous attack. The threats are 16... a4 and 16... Ra6.
Anish Giri also criticizes 12. Nxe5 from Anand.
[Event "FIDE Candidates 2014"]
[Site "Khanty-Mansiysk RUS"]
[Date "2014.03.13"]
[Round "1.3"]
[White "Anand, Viswanathan"]
[Black "Aronian, Levon"]
[Result "1-0"]
[WhiteElo "2770"]
[BlackElo "2830"]
[ECO "C88"]
[Opening "Ruy Lopez"]
[Variation "closed, 7...O-O"]
[EventDate "2014.03.13"]
[FEN ""]

1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 Nf6 5. O-O Be7 6. Re1 b5 7. Bb3 O-O 8. h3 Bb7 9. d3 d5 10. exd5 Nxd5 11. Nbd2 Qd7 12. Nxe5?! Nxe5 13. Rxe5 Nf6?! (13... Nf4! 14. Nf3 Nxg2! 15. Kxg2 a5!!)

@Wes This actually happened today in the game Ivanchuk-So.

ya, what an embarrassment for a Super GM. He should follow our humble chess.stackexchange.com forum and learn a thing or two :p


text:
Kramnik - Karjakin in the FIDE Candidates 2014, was 8...f5 correct?
In the game between Kramnik and Karjakin shown below, the opening was a bit strange and the resulting position was odd. I am wondering, was 8...f5 correct? Was it a novelty of sorts or when did the game leave the established opening theory in this line? Thanks!
[Event "FIDE Candidates Tournament 2014"]
[Date "2014.03.14"]
[Round "2"]
[White "Kramnik, Vladimir"]
[Black "Karjakin, Sergey"]
[Result "1-0"]
[FEN ""]

1. d4 d5 2. c4 dxc4 3. e4 Nf6 4. e5 Nd5 5. Bxc4 Nb6 6. Bd3 Nc6 7. Be3 Nb4 8. Be4 f5 9. a3 fxe4 10. axb4 e6 11. Nc3 Bxb4 12. Qh5+ g6 13. Qg4 Bxc3+ 14. bxc3 Qd5 15. Ne2 Bd7 16. O-O Qc4 17. Ng3 Bc6 18. Ra5 O-O-O 19. Rc5 Qb3 20. c4 Kb8 21. Qxe6 Rde8 22. Qh3 Nxc4 23. Rxc6 bxc6 24. Nxe4 Nb6 25. Nc5 Qd5 26. Rc1 Ka8 27. Na6 Kb7 28. Nb4 Qf7 29. Qg4 Nd5 30. Nxc6 Re6 31. Na5+ Ka8 32. Qe4 Rb6 33. g4 h5 34. Rc5 Rd8 35. Nc6 Rxc6 36. Rxc6 hxg4 37. Rf6 Qh7 38. Bg5 Qg8 39. Rxg6 1-0

Stackexchange should provide a way to quickly "download as PGN" the game you posted.

@Wes yep, could be useful...post on the Chess Meta site? Cheers.

Added the feature request here - http://meta.chess.stackexchange.com/questions/302/request-to-allow-download-as-pgn-feature
Hopefully they'll implement it soon!

8...f5 is no novelty. It is a well known line and has been played successfully before by strong players like Adams, Salov and Karjakin himself.
8...f5 is absolutely the correct move in the position, because it practically forces White to either surrender his strong central pawn on e5 or give up his strong light squared bishop for Black's knight on b4. I demonstrate a line below showing what happens if White tries to avoid both these possibilities with 9. Bf3.
   [FEN "r1bqkb1r/ppp1p1pp/1n6/4Pp2/1n1PB3/4B3/PP3PPP/RN1QK1NR w KQkq f6 0 9"]

   1. Bf3 f4! 2. Bxf4 Qxd4 (2... Bf5!?) 3. Qxd4 Nc2+ 4. Kf1 Nxd4=

Thus, in the above position, White is practically forced to concede one of the two advantages.
Normally, White players preferred to play 9.exf6 for "obvious" reasons like the light squared bishop is stronger than the knight on b4 and is White's most valuable piece in launching a kingside attack.
Thus, in this position the move 9. a3!? must have come as a complete shock to Karjakin. It has never been played before at Grandmaster level and was only played once before in Janczarski,M (2335)-Bartel,M (2273) Warsaw 2013 (source here).
   [FEN "r1bqkb1r/ppp1p1pp/1n6/4Pp2/1n1PB3/4B3/PP3PPP/RN1QK1NR w KQkq f6 0 9"]

   9. a3!?

Whether 9.a3!? is good or bad is a different question. It seems to me that after
   [FEN "r1bqkb1r/ppp1p1pp/1n6/4Pp2/1n1PB3/4B3/PP3PPP/RN1QK1NR w KQkq f6 0 9"]

   9. a3 N4d5 10. Bf3 Nxe3 11. fxe3 g6 12. Ne2 Bh6!

Black is perfectly fine.
Conclusion: 8...f5 is correct!


text:
Why is it a good idea to teach chess in schools?
There is a "movement" towards teaching chess in school and perhaps introduce chess as its own subject. What are the advantages of teaching chess at schools? In what ways is chess similar to other school subjects (e.g. math)? What "life skills" will the students learn by learning chess?

The way this question is formulated, I find it hard to accept any answer given so far. Since the question itself assumes it is a good idea to teach chess, and on top of that, in schools. Hmmm.

What are the advantages of teaching chess at schools?

That depends. If you like chess, the advantage of having chess classes for free from good teachers (assuming they are good) is that you play your favourite game / learn something you like / have people to play with / all of this is free. It is really good for average chess players (who will be able to find steady income by teaching others).
But knowing this you have to understand that there are people who do not like chess. How will you feel if right now you will be forced  to learn how to play the triangle (kind of funny musical instrument that I by myself find kind of lame). What would you think if your child instead of math/biology/whatever subject you find important would be wasting his time learning triangle/chess which in my opinion will not help his career (assuming he will not become pro triangle / chess player)?
Also forcing a child to do something is not a good way for him to like this something. I enjoy playing chess, but if when I was child I would be forced to go study chess - most probably I would hate this game. There are a lot of places for a person to play chess in his free time enjoying it, so why spoil the fun with compulsory things?

What "life skills" will the students learn by learning chess

What life skills will you gain by swimming / playing the triangle? You will not drown fast in case of flood. You will become a good swimmer. You will learn how to play the triangle and will be able to properly hear/understand music. People can argue that music will make you a better person, swimming will make you more fit, organized, but I am not aware of the proper studies conducted. What skills will you gain by training to solve IQ tests every day? Will you perform well in physics, economy, history, programming? Highly doubtful, and average person who spends 1/10 of your time learning one of these things will perform better. IQ tests will make you a better IQ test solver.
The same way with chess - by learning chess you will learn how to play chess, maybe will learn abstract thinking, thinking ahead and analyzing your options.
I by myself was speaking with some of the top 200 grandmasters and based on their discussion, chess is hard to make money on. You spend thousands of hours on learning preparation, dedication to mastery. And if you are not in top 20 it is really hard to get normal money out of it. Yes, you can publish books, create videos, participate in paid tournaments (which requires a lot of time and effort), but after this amount of time spent in economy you can secure a steady good income.

Your answer is food for thought and brings up important points. Your conclusion is that chess only teaches chess and not much other useful skills. Therefore, it should be an optional and not mandatory activity. Right?

The chess mostly teaches you how to play chess. It may be teaching you how to think ahead and abstract thinking, but if you want to learn abstract thinking I think there are other activities which will teach this better. I definitely think that forcing someone to play a game is not a proper way. If a child will like the game, he will find a way to learn. Right now there is huge amount of free chess websites, databases, books and other materials.

I think you're right. It's really the forcing kids to study chess that's bad. There's probably a tendency that those who are made to play it are also made to study it and learn it which is why a lot of those who are made to play it don't like it. I came up with a similar conclusion on my own before I read this answer that I remember. The brain has its own natural method of thinking which can make them really smart in their own way. I think that for a developing brain, they don't like doing things differently because it's not their natural method. Also for a developing brain, when they're

stopped from using their own natural method of thinking by being made to study chess, I think their gaining of smartness slows down. I upvoted this answer because I like how you explained that forcing a child to play or study chess is bad.

The Benefits of Chess in Education
Take a look at The Benefits of Chess in Education (original link) from the Kasparov Foundation, which gives a detailed overview about the benefits of teaching children to play chess.
The document describes among other things the following points:
Academic benefits

Focusing: Children learn to concentrate, because they have to if they want to play good
Visualizing: Children have to image a sequence of actions before it happens
Planning: Children need to plan longer goals and take steps towards them if they want to win
Weighing Options: Children need to weigh options. They are taught not doing the first thing that pops into their mind.
Furhtermore: thinking ahead, analyzing concretely, thinking abstractly, juggling multiple considerations simultaneously

Social benefits
Chess...

... often serves as a bridge to bring together children of any kind
... helps building friendships
... teaches sportsmanship (how to win graciously, how to lose - like in other sports clubs)

Thanks for the reference! What do you think are the three best points in this document? (If the link is "dead" someday, it would be nice if your answer kept some of the key information). Cheers.

I will edit my answer with some key points @RauanSagit ;)

Link is finally dead, replaced it with an archived version.

The following study holds that chess in schools helps students with low-level gains in intelligence, but no high level gains.  In other words, if I'm correct in my memory of the study it can teach "life lessons" like sports, but with no gains in intelligence versus sports.  So, knowledge of the game would only lead to knowledge in the overlap of fields.  Of course, depending upon your view as to the size of "chess-related" mathematics and computer science this would affect your judgement as to the effectiveness of teaching the game.
The paper is below, judge for yourself.
This flies in the face of what I first thought, but is an interesting take.  As one who publishes in the field of "chess-related" mathematics and played scholastically for 12 years (yes 1st grade through 12th), I say the paper underestimates the vastness of the overlap between mathematics, computer science, and chess (not to mention sociology, philosophy, and other fields).
http://people.brunel.ac.uk/~hsstffg/preprints/chess_and_education.PDF

One paper hardly makes a scientific consensus

One would expect if there were high-level gains for the chess player the experiment that shows it would be able to be duplicated.  However, we have many years of mixed results, as pointed out in the paper!

https://www.chessforsuccess.org/program/study
http://www.championshipchess.net/research.html
http://psmcd.net/otherfiles/BenefitsOfChessInEdScreen2.pdf
One election should not decide my fate for four years, especially when my "vote" was not elected.

I think a lot of this debate centres around differences between boys and girls and men and women. If we are not allowed IQ or intelligence skills, then what could we possibly  actually mean by "life skills" - sometimes, this is not an easy question either at the chess club,or in the classroom, or outside the pub at closing time.... I could go on. (But I won't). Will they eventually give us a "Life Quotient" and will it be measured by the number of kids you've got, or divorces you've experienced -- will it be means tested???? As I say I could go on.

Chess is a fun and interesting game to learn and play. It has many benefits for youngsters and thus it is important for the chess in schools to take shape.
Founding my own project, where I teach chess to underprivileged and blind children, I discovered the many benefits of chess for these children.

Chess builds up confidence and makes the players motivated.
It also provides a recreation for the students who otherwise waste their time on television and video games.
It provides a growth medium for the brain and is like a brain gym. In the future, the risk of Alzheimer can be prevented.
Chess makes the player positive and focused.
Chess also helps a player to excel in other school activities.
It develops a strong personality for the player and helps the player to survive strong battles.
It leads to a change in the thinking and pattern recognizing abilities. Improvement in both these areas are visible in most chess players.

There really cannot be any educational value in just knowing the moves of the pieces, or memorizing how to mate with a Rook, or making random moves on your side while another kid makes random moves on the other.
The justification has to be that a good teacher who is also a chess enthusiast will find the game to be an inexhaustible source of teachable moments, and will use these to convey valuable lessons whether thay are on the syllabus or not. Very few studies of the benefits or lack of benefits ever seem to describe HOW the game was taught, and therfore offer no valid basis for any conclusions


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What are the benefits of becoming a chess (player, team or tournament) sponsor?
It is probably well known that Magnus Carlsen is sponsored by Arctic Securities. An example of a tournament sponsorship is the Annual Rilton Cup sponsored by the Rilton Foundation. What are the benefits of sponsoring and becoming a partner of a chess player, team or tournament? Additionally, can you think of any more examples of sponsorships in the present and past?

How about this benefit?

It is probably well known that Magnus Carlsen is sponsored by Arctic
  Securities.

Being well known is the benefit. One minute ago I had not even heard about arctic securities. And now I know, as well as may be thousand of other people watching/reading about the game. Why Vodaphone or whatever is sponsoring football? Do they care, do they have any connection to football? - No.
The idea behind sponsorship is always the same - let people know about you or see your sign.
Answer to Rauan's comment:
I do not want to disappoint you, but there is nothing unique about sponsorship in chess. In business all that matters is money / revenue / stock prices / public awareness.
Why did IBM gave half a million in 1996 to Kasparov for a match with a machine? They did not care about chess, they cared about advertising and stock market price. That's why they cared so much about the rematch in 1997 giving $1.1M for it and offering $0.7M to a winner. Not a lot of chess players who know about the matches, know how this ended up for IBM

IBM estimated it received $500 million of free publicity from the
  match, and IBM stock prices went up over $10 to reach a new high for
  the company.

I think this is one of the best money investments.

Spreading the word about your trademark through sponsorship, yes, makes sense! :) But that could be true for any sort of sponsorship. Isn't there anything more, something unique when sponsoring chess?

@RauanSagit the answer is modified to answer you follow-up question.

I totally agree. I will have to think a bit more about how to formulate a question in order to get the answer I am "fishing for". Firstly, that certain companies are probably more willing to associate their brand with chess. Secondly, that chess players and enthusiasts form their own "customer audience" that could indeed be a nice one to target.

@RauanSagit But it is better to ask a new question, because may be after reformulating my answer will be completely off-topic. Sure - IBM wants to be connected with chess because it is computing and intelligence. And also people who likes chess are mostly more intelligent than people who like football. There is a certain entry barrier. There are millions of people who watch football/boxing without knowing how to play/never been in sparing and think that they know what a team/boxer should do without even knowing the rules. You can hardly find situations like these in chess.

My conclusions so far is that a sponsor is indeed interested in a return on investment. When it comes to chess, as in any other competitive sport, it is easier to find this at the very highest level (top players, top teams).


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Could Karjakin have grabbed on g5 at move 56 against Anand in the Candidates 2014?
After 55...Rb2, we got the following position in Karjakin - Anand (Candidates 2014, round 13). Well, how about Nxg5, does it work?
[White "Karjakin"]
[Black "Anand"]
[FEN "8/8/6k1/4p1p1/4P1Pp/5P1N/1r1BK3/8 w - - 0 1"]

1.Nxg5 Rxd2+ 2.Kxd2 Kxg5 3.Ke3 h3 4.Kf2 Kf4 5.Kg1 Kg5 6.Kh1

Seems better (winning?) for white. Am I missing something?

Karjakin also thought h3 was forced and only calculated that line. He missed Kf6 and Kh6. Kg6 loses.

What amazes me is that a world class grandmaster like Karjakin failed to correctly evaluate this endgame. It should have been "elementary" for him.

3...h3 is wrong. The key is 3...Kf6!
[FEN "8/8/5k2/4p3/4P1Pp/4KP2/8/8 w - - 2 4"]

Note that:

White's king has to stay in the h-pawn's square, so it can't try to walk around the pawns.
Once white's king gets to h3, black should always be able to answer ...Kg5. If he does, then white's king can only retreat, unless he tries f4 there:

[FEN "8/8/8/4p1k1/4P1Pp/5P1K/8/8 w - - 8 7"]

1.f4 exf4

If anyone is better off here, it's black, but it's still a draw.

Or white can play 4.f4 immediately.

[FEN "8/8/5k2/4p3/4P1Pp/4KP2/8/8 w - - 2 4"]

4.f4 h3! 5.fxe5+ {What else?} Kxe5 6.Kf3 h2 7.Kg2 h1=Q+ 8.Kxh1 Kxe4 =

So the pawn endgame is a draw.

You suggested 3... Kf6, I suggested 3... Kh6. Both moves work equally fine, what black should avoid is 3... Kg6? because of 3... Kg6? 4. f4 h3 5. f5+.

The pawn endgame is a draw. Black doesn't play h3 until white plays f4, for instance
[White "Karjakin"]
[Black "Anand"]
[FEN "8/8/8/4p1k1/4P1Pp/5P2/3K4/8 w - - 0 1"]

3.Ke3 Kh6 4. f4 h3! 5. Kf3 exf4

If white doesn't play f4, then black only needs to be ready to answer Kh3 with Kg5, but that is never going to be a problem.


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Is this endgame a draw (hacked - TestViking)?
In my recent online blitz video, I got the following endgame with the black pieces. With white to move, the game went as follows
[White "hacked"]
[Black "TestViking"]
[FEN "8/3k2p1/1p1P1pP1/p1p5/P1P1PK2/8/8/8 w - - 0 1"]

1.e5 Ke6 2.exf6 Kxf6 3.d7 Ke7 1/2-1/2

...white offered draw and I agreed. Was the position a draw or did one of the sides have a win or winning chances?

What did the engine say?

@Rafiek StockFish DD says it is equal after 1.e5.

Yes, it was drawn all along. 1...Ke6! was the only move for black to draw since he cannot allow white to force ...gxf6, nor allow the white king up to support the d-pawn. After 4.Ke5 Kxd7 5.Kd5 there's no way for either side to make progress as the kings will just be shuffled between d5/e5 and d7/e7. There is one practical chance/trap that might be worth trying before agreeing to a draw; black can play 5...Kc7 and see if white goes for 6.Ke6, in which case black wins with 6...b5!, forcing the creation of a passed pawn and queening first. As long as white spots this and plays 6.Ke5 instead there's nothing more to do, though.
Edit: I realized black cannot play Ke7 at the end as it loses to Kc6. However, Kc7 still draws as before due to white being unable to play Ke6.


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What material handicap would be required to compensate for a single double-move?
Consider the following chess variant:

Black can, once per game, make two moves in a row (the second move may not capture the King)
To compensate for this advantage, Black gets a material handicap
Otherwise, the standard rules of chess apply

The question is, approximately what material handicap would be needed for the game to become roughly balanced? It is clear that making two consecutive moves, even only once per game, is a tremendous advantage. My guess is that at least a Queen handicap is necessary, since it is trivially easy to capture White's Queen with two consecutive moves once the pieces are out.
Has this chess variant been studied before?

+1 Very interesting variant, but I doubt it would be possible to answer this without making speculations.

One could program the variant into a computer and do a Monte Carlo Tree search, which should give a pretty good idea of how the balance is. I must admit, though, that I'm a bit too lazy and inexperienced with chess engines to attempt that :)

I doubt that will work either, because chess programs need evaluation functions. How will you evaluate a position if you know Black still has the extra move option?

@Wes some sort of "double move" wrapper can be written around an existing engine to handle this sort of situation.

@RauanSagit but just how exactly will you evaluate the position? The evaluation function is unknown as of now, because there are no "masters" in this variant of the game yet.

Monte Carlo Tree search engines do not use (at least do not necessarily need) an evaluation function. They work by playing out thousands of random, complete games and deciding on a move based on the worst outcome they encounter. The only terminating condition in this case would be either draw or checkmate, which is unchanged for this variant.

My point is, how do you know you're working with a good sample? In regular chess, if you take the games of all top chess programs or grandmasters, you know you're working with a good sample. But here, how will you know the quality of the random games you select?

@Wes my thought was that the "double-move wrapper" would feed the same position plus one extra move to a regular engine. The list of plus one extra move would probably have to be exhaustive (i.e. include all possible moves for a given position) in the very first version of the wrapper.

I don't know the answer to your question, but there is a simple way to make the game fair: Before the start of the game, have an auction where the players bid how much material they are willing to give up for playing with the black pieces.

@RauanSagit the engine can surely calculate all moves with the wrapper, but how does it evaluate the position? Good for White or good for Black? By how much? We don't have good information about how to assess the position if Black has an extra move at any point. Consider king and pawn endgames - normal evaluations might be a draw, but maybe black's extra move makes it completely winning at some point. It's "unknown" or "unclear" evaluation, which doesn't help the machine.

@Wes: You don't need any assumptions about the quality of the sample. The whole point of Monte Carlo methods is that you sample randomly and use the average outcome to guide you, invoking the law of large numbers. If a move leads to random games where you get checkmated 90% of the time, it's probably not a good move.

@DagOskarMadsen: Your proposal makes the whole system, i.e. the auction plus the chess game, a fair game in the sense of game theory. The chess game itself, however, will not necessarily be fair, even if both players were satisfied with the outcome of the auction.

@limulus - The way I understand it, the MC method is appropriate where the next step in the tree is random. In chess, the next step is not random, but determined by the value function of the player - are you sure an MC method without an evaluation function will provide a realistic picture? My gut feel is that the results of the MC simulation will be skewed by countless positions that will never occur in a real chess game.

Queen is too much, black should do two moves to take queen in best case, but then, black just became equal in material, on the other hand white is two move ahead, one because is white, second because black used one of his moves to get equal to white, so I think knight + rook is more reasonable.

I do not fully understand the "Black can, once per game, make two moves in a row" part. Can Black only open the game this way like 1. e4 d5 and then play dxe4 ? Or Black can play twice anytime he wants if he still has this option available ( you said he can do this only once in the game ) ? Can you please clarify? Thank you. Best regards.

Black would easily be able to trade a Knight or Bishop for the White Queen. Thus, White would need about 2 pieces extra. Or maybe just an extra Rook.  Basically, it would be N+N+B vs Q, or B+R vs Q.

@DagOskarMadsen This is not obviously fair actually. If one could prove that X amount of material gives you advantage, but any material more gives disadvantage, then the person who bids first has an advantage.

The question can never be answered in a general fashion. Every move has its own perks and advantages. The major variables are these:
Is the same piece allowed to move twice or can black move two pieces once?
Are captures allowed? With just one move of the king's pawn already made, it is possible for any party to capture the opponent's queen within two moves. (Or put them in a position where it cannot escape capture in the next few moves). Here the price for two moves is AT LEAST a queen (since the two moves party would not only have captured the queen, but also invaded inside the enemy ranks).
Starting from midgame, two moves can easily put the opponent in a mate-in-x position where they cannot avoid mate. For example, if one has several mating combinations available, there can be no possible compensation to that!
All in all, I think the option of two moves can/should be made available only in the opening and the price is the queen. It is disastrous and potentially game-losing to allow the opponent double moves in the middlegame or endgame and there can be no compensation to that.

You state that there can be no compensating mating, but if you give up all your material then you cannot mate at all...

My feeling is that a queen would be too much.
My reasoning is that without a queen it is very unlikely that the double move will ever lead to a winning attack. So at one point the double move will have to be used to "win" the queen, but if white takes care to always protect the queen this will probably lose some material.
Something materially equivalent like both rooks strikes me as better, because it doesn't impede blacks dynamical chances in the same way. Possibly rook+knight or rook+bishop would be even more balanced.

In most opening gambits, a pawn is worth two tempi(Two moves). So I guess that a pawn would be fine. To be more precise, the f pawn. I think that is the most logical way.
But yet there remains a problem. I can mate you like this:
  [Title "White to move"]
  [fen "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"]

  1.e4 e5 2.Bc4 Bc5 I use the move now 3.Qf3 h6 4.Qxf7#

I used h6 as a waiting move to show that a double move is made.
In a similar way, a player can trap or take a big piece, such as a queen.
So the rules so far:

White(Or black) lacks his f pawn.
The person with the right to double move cannot mate. If a mate is inevitable, he cannot use the double move.
The person with the right to double move cannot take a piece. If taking a piece is inevitable, he cannot use the double move.

About check now. I do personally think that if you are checked, the double move doesn't count, so:

The person with the right to double move cannot check. If a check is inevitable, he cannot use the double move.
 [Title "White to move"]
 [fen "rnbq1rk1/pppp1p1p/5BpQ/4p3/4P3/8/PPPP1PPP/RN2KBNR w KQ - 0 1"]

But there are also positions like this. So this idea comes up:

Right after the double move, the non-double move player can exchange one of his pieces for a piece of equal value. You can exchange a bishop for a knight. You cannot exchange say, two rooks for a queen and pawn.

So I think that this is the best way to answer your question.
Hope it helps.

I don't understand your answer. Up to the first line, you stand great, but then you digress and simply provide different rules for the game.

I use reasoning to support what the first sentence clears out. Please reread it.

You prove that in the chosen opening (1.e4 e5 2.Bc4 Bc5??) Bc5 is a losing move. This is a consequence of allowing White the double move (the question is about Black having a double move) and it does not follow that the rules need to be fixed to make Bc5 a good move...


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Setting DGT North American clock for two time controls
Does anyone know how to set a blue DGT North American chess clock to the time control of:
2 hours for the first 40 moves, with 30 minutes added thereafter, with 10 second delay throughout the course of the game?
I found the following information here (http://www.amazon.com/DGT-North-American-Chess-Clock/dp/B00312D2OU) and hope that it is false:

Most disappointing to me is that, though it claims to have all major North American time
  controls, it is missing an important one. The time control 40 moves in 2 hours + 1 hour
  thereafter WITH a 5 second DELAY. This is fairly common (at least in Texas) to have a
  delay on the control, but this clock does not do the move counter (i.e. automatically add
  time after the fortieth move) with a delay. It will do it with an INCREMENT, but not a
  delay.

You're right, I can't prove that I own a DGT 3000 clock. So don't take my unregistered word for it. Instead download the PDF manual and scroll to page 17, where you can read the following: "Only in a period with the FISCH method a number of moves (Moves ≠ 000) can be set. After this FISCH period it is possible though to choose another method. When the second period does not have the FISCH method, then the period after that can only start again when a player reaches 0.00 The settings for DELAY and US DELAY are similar. In the center of the display “DLY” will be shown when the delay time can be

You can almost do what you're describing with this clock.
In actuality, it is better to NOT add time after move 40, but instead add the extra hour after one side's clock runs to 0:00.  This is because it is fairly common for the wrong side to start (i.e. time would be added after black's 39th move) or for the clock to be pressed an extra time which would result in time being added after white's 39th move.  This is problematic because now the clock says that you have, for example, 61 minutes left when in reality you would only have a minute to make your move.
So with that intro, it is very easy to setup the clock with two time controls and a 10 second delay.  As described above, the extra hour is added after the time first goes to 0:00.  A small flag icon is displayed and the clock continues counting down from 59:59.
In order to set the clock this way, you would use preset 23.  (Turn the clock off then back on and press the + button or - button until 23 is displayed)
After selecting preset 23, set the main time for the first time control to 2:00:00 on the first screen.  Then the clock will display 1 | 0.00 with the word "delay" in small print underneath the time.  This is the delay for the first time control.  Set this to 0.10 for a 10 second delay.
Now simply repeat these steps for the second (and possibly third) time control and you're ready to play.
One last caveat, before you start the game (by pressing the play/pause button), make sure that white's side of the clock is raised by pressing black's side.  Most clocks can be started by simply pressing black's clock at the start of the game, but this clock needs to be unpaused in order to begin.

Thank you for your thorough response! I will let you know if I have any further questions.

No problem.  For what it's worth, if you're buying a new clock, I would probably recommend a different model.  While this can do everything, there are enough drawbacks that I would prefer a Chronos despite the price difference.

My biggest complaint (and maybe just my own preference) is that it only displays seconds once it goes under 20 minutes.  I really prefer to see the seconds from move 1.  The other drawback is that it doesn't show how many seconds during the delay period.  As a time pressure addict, I almost need to see how many seconds before the main time starts ticking to avoid flagging.

The DGT North American and DGT 2010 were designed for different markets. DGT's assumption was that one style of clock delay/increment would prevail in the US, and that's what the NA is equipped with. The other is what prevails in other countries, which is what the DGT 2010 uses. They are otherwise identical.
FYI: The DGT 3000 (a newer and more expensive model) offers both types of delay/increment mechanism.

As the new owner of a DGT 3000 I am disappointed to inform you that it is only capable of Fisher delay (increment type) for any time control with a set number of moves like 40/2 hours followed by whatever. There is no way for it to do a US or Bronstein delay for a given number of moves.


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Help with discovered checks
I'm new to chess and I've found that while certain tactics come relatively easily to me(double fork), certain others are quite harder.
I've been missing out on a lot of opportunities to take advantage of discovered checks. Is there something I should be looking out for? Has anyone else faced a similar difficulty?

As you keep practicing tactics, you will discover that you discover discovered checks very easily. So just keep playing and practicing tactics. http://chess.stackexchange.com/questions/5379/what-are-the-options-for-solving-puzzles-online-and-tracking-progress/5381#5381

A Discovered Check is a "discovered" attack against a King--when a pawn or piece moves aside, to reveal a check by another piece. It's a powerful weapon, because check is given by a piece that does not have to move--and therefore, the piece that does move is free to make other threats, or even captures.
To a certain extent, you will naturally begin to see opportunities for discovered checks as you play more, because they, like all discovered attacks, are all about lines of influence. Tactics practice--all tactics, not just discovered check tactics--will help you begin to visualize these without searching for them specifically. A google search for "chess tactics" produces a decent selection of online tactics trainers.
To look for discovered checks in particular, look for pieces that would be checking the opponent's King, if not for one of your own pieces blocking the way. For example, in the diagram below:
[FEN "r2q1rk1/pp1n1ppp/3p4/2b1p3/3nPPQ1/2NB4/PPP3PP/R1B2RK1 b - - 0 1"]

Black to move.
Black's Bishop on c5 would be checking White's King, if not for the Black Knight on d4. If Black's Knight moves, it will reveal a discovered check. In fact, Black has an opportunity to win material here:
[FEN "r2q1rk1/pp1n1ppp/3p4/2b1p3/3nPPQ1/2NB4/PPP3PP/R1B2RK1 b - - 0 1"]

1...Nxc2+! 2.Kh1 Nxa1

Even though the pawn on c2 is defended by White's Bishop, the Black Knight may take it with impunity, because White must respond to the discovered check. Then Black is free to win a further exchange, Knight for Rook, after White's King runs away.

Pawns can reveal a discovered check as well, and they're sometimes much more dangerous than pieces, since they can effectively threaten anything, and even advancing at all can make them powerful weapons.
In the situation below, material is equal and there's a lot of tension on the board, but White has a devastating discovery that wins instantly...
[FEN "1k4rr/pp1n1pq1/2b2p2/2p1P3/5Q1p/2N2N2/PP3PPP/3R1RK1 w - - 0 0"]

1.exf6+!

White's pawn will take the Black Queen next turn, with no real repercussions, and he should go on to win with ease (if Black doesn't simply resign on the spot!).

One common pattern is often called a "windmill": where one piece takes advantage of a trapped King by repeatedly alternating between giving check and discovering another check. The position is from a somewhat famous game by a 13-year-old player you might have heard of:
[White "Donald Byrne"]
[Black "Bobby Fischer"]
[FEN "r3r1k1/pp3pbp/1Bp3p1/8/2bP4/Q1n2N2/P4PPP/3R1K1R w - - 0 0"]

1.Kg1 Ne2+ 2.Kf1 Nxd4+ 3.Kg1 Ne2+ 4.Kf1 Nc3+ 5.Kg1 axb6

By the end of the windmill, Black has already gained a Bishop and a pawn, and he will soon pick up the Rook on d1 as well, and go on to win handily.

A common thread in discovered check tactics is long, open lines directed at the enemy King. Because discovered checks are generally delivered from a medium or long distance, an open board and few pawns around the King make them easier to engineer. Look for pieces that could deliver check, if only some other piece or pawn was removed.
If you find a discovered check, look at all the places that the discovering piece could move: can you take free material? Make other threats that your opponent can't answer? Use a windmill to pick up many different objectives? Discovered checks are one of the most versatile threats in the game--when you get used to seeing them, your tactical levels will improve dramatically.

I would say, look for any piece lined up against an opposing king, regardless of what is currently between the two. I.e. even if some opponent's pieces are also currently "in the way", they may move at some point also. As to helping "visualize" the concept (of discovery), this may be even easier to "see", and may reveal other possibilities to your tactical mind as well (e.g. discovered pin).

The Discovered Checks (Attack) is a form of double attack.  In these sorts of attacks, typically a stationary piece gives check while the one that moves is free to threatens another piece.  Creating a threat that cannot be parried is pretty much the goal of chess. Discovered attacks do exactly this.
They are something you want to get good at spotting.  Your opponent will have to spend time to prevent them from happening.
Here are some tactics exercises.  Play through them, then search for others.

Discovered attacks are almost like reverse pins. With a pin your piece prevents or inhibits and opponent's piece from moving by threatening to capture a piece behind it. With a discovered attack, your opponent piece is threatened by moving your piece exposing it to attack from a piece behind it.
Here's what you should look out for:

Any time you can move a piece with a discovered check, you should carefully consider all of those moves. In this case, the piece that moves is likely to be able to move freely without threat of capture. This makes it possible to threaten or capture a valuable piece with perhaps no defense or move in for mate.
Any time you can move a piece and discover an attack on your opponents Queen. If your opponent leaves his queen where it may be attacked by discovery, you may be able to use it to your great advantage to win a piece or trap the queen.
Any time a piece is undefended and subject to a discovered attack. Undefended pieces are always weaker than defended pieces.


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What chess *scoring* alternatives exist?
Chess (often being classified as a sport) stands almost alone among sports in that its results are of a strictly ternary nature that is not quantified any further: The only possible outcomes are a win, a draw or a loss.
While the same is of course true for most team or combat sports, virtually all of them go a lot further by basing the result on some sort of point score, which says a lot more about the match than merely who won: A 6-0 win in association football is not the same as a 2-1 (the first being a "crush" and the second being a rather narrow win), and a 3-3 draw is not the same as a 0-0 one (the first one indicating a wild game, the second a tenacious one). Further in-game metrics such as "ball control" and "shots on goal" are often employed to paint a high-level picture for spectators.
Given that literally hundreds, if not thousands, of variants to chess rules exist, I should be surprised if no one has ever proposed an improvement to how chess is scored, but alas, I have not found any material on that subject. I'm looking for a new angle to see top-level matches from, where, when analyzing games, one often cannot help but feel that some are won by a larger margin than others, and similar insights.
Do any alternatives to ternary (win, draw, loss) chess scoring exist?

I think the only alternative would be in match play or comparing a player's score across multiple games against another player or players.
For example, in a 12 game match between two players:
(+3 =8 -1) would be worse than (+5 =6 -1)
even though the first player won both matches.
Scoring by material count or number of moves played would not be beneficial. If the number of moves mattered, with shorter games being considered crushing defeats, players would just refuse to resign and drag the game out. On the other hand, I can lose in two moves without losing any pieces.
The only thing that seems to make sense is to compare score across multiple games against an opponent or field of opponents. You may have a better comparison considering a GM's total score in a tournament with many rounds. In a 9 round tournament, a 9.0 score would be crushing the competition. Winning the tournament with 6.5 would be less of an accomplishment.

Sometimes the media would report the number of moves the game lasted as some kind of indication of how badly an opponent was "crushed". If Magnus was to lose in less than 20 moves, that could be considered "badly beaten" by whomever he was playing, and I'm sure anybody reporting on it would mention that fact. To make it more sophisticated, you could count the number of moves until one side had a substantial advantage (i.e. Nakamura was losing by move 17, even if he managed to draw it out until move 63).
Another method I can think of is to use the computer evaluation during and at the end of the game. For example, recently Nakamura was +10 against Carlsen in a game (which Carlsen subsequently won) - that obviously gives an indication of what type of lead Nakamura threw away. By looking at the computer evaluation over the length of the game, you can get some idea of who was winning by when (although how you would coalesce that into a single number is something the statisticians may want to have a go at).

Personally, I'm perfectly fine with chess having only a simple ternary outcome. I am always skeptical of using alternative scoring methods. Does 4-0 really mean Liverpool crushed Arsenal? What if the score was 1-0 with 5 minutes left, and Liverpool's forward scored a hat trick while Arsenal was pushing aggressively? Maybe Arsenal even missed 5 good shots on goal during that last 5 minutes. Is it fair that Arsenal is now eliminated due to a worse goal difference?

People have proposed adding a new fourth result for stalemate, where (for example) the stalemated player would get 1/4 point and the stalemating player would get 3/4 points. Unfortunately I don't have a reference at hand.

Such a thing isn't going to happen, but if it were I wonder if there should be a distinction made between situations where there would be a legal (losing) move but for the prohibition against entering check, and those where no pieces would be able to move even if entering check were legal.

Yeah, it would make the theory nicer, but in practice the number of stalemate positions where you couldn't move even if check were legal is vanishingly small; you really have to work to construct one.

I was just thinking of another idea, in case the existing game gets too over-analyzed and needs to be shaken up: what if the game proceeded until the half-move after a player's king was taken.  If by the end of that half-move only one king remains, the survivor gets one point.  If neither king remains, both players get 1/2.  That would mean that a player who was behind could check the opponent's king with a pinned piece; if the opponent takes his king, both players would get a half-point, but the opponent might opt instead to defend his own king.  I wonder how that would affect dynamics?

@supercat Actually, that's been precisely the case at various points throughout the game's history -- it probably won't swing away from {1/2,1/2} again any time soon, or perhaps ever (though I doubt this), but it's been this way for only about a century and a half (or two centuries?).

I know of two.

The ELO rating. Players are awarded points based upon the result of the game versus the expectation. The rating is used to rank players in terms of skill. Higher rating denote higher skill. Higher rating carry more prestige. A higher rating also gives one an advantage in USCF Swiss-style tournaments and higher rated players are paired against lower rated players, giving the former a better chance at a win/loss result that nets prize money.
In some tournaments, draws are awarded .4 points. This makes two draws markedly less valuable than a win and a loss. This has been done to encourage players to play decisive games.

I think the question is after alternative methods to measure the qualitative aspects of a single chess game (i.e. by how much did player A beat player B?). Both your points, although interesting, relate to a series of games.

@firtydank Perhaps. But I offer a different way forward.

The Bilbao 2008 tournament used the FIFA scoring system:

3 for a win
1 for a draw
0 for a loss

It has been used at other tournaments such as the London Chess Classic.
The aim is to encourage 'fighting chess' and discourage early draws as the tournament result favours those who have won most games.

You're confusing score with score.
Except for the game score (notation) and commentary, there's no real to show the action on the board.  Even a material balance could be misleading, as we'd need to differentiate between a sacrificial attack and a lucky mate when losing badly.  We do have an external indicator, ratings*, which, by the difference, can suggest the difficulty of play.
There have been suggestions to alter the score (game result), but these were to reduce the number of (GM) draws.  The only accepted suggestion was to give a win more points for a win that two draws, mainly the 3-1-0 scoring system.  A favorite was to split the point 0.4-0.6 as black has a harder time earning that draw.  Another, misunderstood, system was to split the point based upon the rating difference.  A lower rated player would receive more of the point as his effort in drawing the game could be considered greater.  (Or the opposite is the the higher rated player has the "duty" to make a more decisive result.)  An infeasible system of having a third party judge the game and decide who deserved more points.  This could result in the losing player earning more points.
*Rating effects what we assume.  In a professional game, a 0-0 score makes us infer that the goalie was exceptional or the players were good at defense.  If the game was played by beginners, we might assume that they bumbled every play.

Some have tried it.
But it distorts the game and is illogical for game results although useful to help tournaments create more interest for sponsors.
A win and a loss against a player once with white and once with black has to be equal to two draws against the player again with equal colors for each.


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Is this endgame won for white?
With the missing g and e pawns still on the board and a roughly symmetric position, I made a mistake that led to 17 moves of what I think of as quite difficult defense. My opponent walked into the following fork and then resigned.
 [Title "Game's Final Position"]
 [SetUp "1"]
 [FEN "8/5pp1/7p/1n1R3k/4PP1P/8/8/r3BK2 w - - 6 1"]

I know that I definitely would not have resigned in that position.

Is the above position won for white?

Conceivably, black could play Kg6 and try to put together something like a fortress, or even play g5 immediately after Rxb5. However, I believe the correct continuation would be
1 ... Kg4 2. Rxb5 Kxf4 3. Rf5+ Kxe4 4. Rxf7 g5 5. h5, resulting in the position
 [Title "End of My Main Line"]
 [SetUp "1"]
 [FEN "8/5R2/7p/6pP/4k3/8/8/r3BK2 w - - 6 1"]

with black to move.
From tablebases (e.g. this site), I know that if I instead played 5. hxg5 and black responded with hxg5 then the position would be a draw. In fact, even if all three remaining pawns disappeared and it became my move, the position would still be a draw. Thus, white's strategy at the end of my main line presumably involves threatening/trying to win the pawn on h6, possibly after exchanging rooks.

(I don't know whether or not the "rook endgame" tag is appropriate, since there's also a bishop on the board.)

The final variation you give seems to be the only way to resist (the 1...Kg6 you suggest is nonsense however). But in the final position after 1 ... Kg4 2. Rxb5 Kxf4 3. Rf5+ Kxe4 4. Rxf7 g5 5. h5 even if it is hard to demonstrate a win for white the general idea is that white will be able to consolidate by bringing his king near to its pawn and win in the long run. But you are right that resignation was clearly premature.

The "mainline position" is won for White, but the lines are too long to post them here. Is there a concrete problem you face in converting this position into win? As for the position after the blunder ( Rd5+ ), it is still won for White but it does require precise execution as Black will significantly reduce the number of pawns with 1...g5, followed by ...f6.

A gut feeling is that Black would have a chance against a light squared Bishop. With a dark-squared one, Black pawns are doomed, and since H8 is also dark, White has a luxury to exchange Rooks. No concrete variants, but all odds are for White to win.

According to my analysis, it seems like a clear win. Black can't force the exchange of the remaining white pawn,  White has the Bishop of the appropriate color, and Black can't prevent White to improve the position of its pieces.
An important tactical finesse:
1..Ke5 2.Kg2 Rxe1 3. Re7+, winning the Rook.
Another important idea:
1..g4 2. Rf6 g3 3. Rg6! (3. Rxh6 g2+ 4. Kxg2 Rxf1 5. Rf6 =) 3..Ra5 4. Rg4+
and the g pawn falls.
(Note that 2. Kg2 is also possible, with the same idea as above.)

It should be a matter of time for Black to lose its remaining pawns, since the black King is cut off from them.  I can't offer any concrete lines, so perhaps I'm wrong here. But what I know is that
W: Kf1, Be1, Rh6, h5
B: Ra1, Kf5
is a win in the tablebases. It does not seem to be possible to prevent White to play Rh8 and h5-h6, after which the pawn is immune. As soon as it gets attacked by some Rh2, White has Rg8+, repeating the same tactical theme as above, or Bd2, protecting the pawn directly.
I've played some games with an extra Black pawn, and I have yet to save one game against Stockfish. One annoying bug of having a pawn on g4 is that black King can't move on g4.

Stockfish gives your "end of my mainline position" as winning for white(+2.62). I am attaching the whole line below. It does seem that while the rook protects the bishop, the white king can quickly head over to the black pawn chain.
Score: 2.62
Best: 1. ... Kg4   Ponder: 2. Rxb5
Time: 31.4s   Depth: 16
Server: srv01   CPU #1: 24%
Engine: Stockfish 1.8 64bit

1. ... Kg4 2. Rxb5 Kxf4 3. Rf5+ Kxe4 4. Rxf7 g5 5. h5 Ra6 6. Kg2 Rc6 7. Kg3 Kd5 8. Kg4 Rc4+ 9. Kf3 Rc1 10. Re7 Rb1 11. Bf2 Rb3+ 12. Be3 Rc3 13. Kg4 Ra3

I tried to put up Houdini 6.02 and a tablebase win is reached , albeit it is a mate in 48 !!! According to seven piece tablebases, White is even forced to give up the pawn toward the end but obtain a winning Philidor position! Yes , White wins , but has a lot of work to do.
Position WHITE Rook in h6 Bishop in g3, pawn in h6 , King in g2 BLACK Rook in d1 , pawn in g5 King in f5. BLACK to move : White mates in 48 moves.

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