World Cup: passed pawns vs extra piece [fen "N7/P3pk1p/3p2p1/r4p2/8/4b2B/4P1KP/1R6 w - - 0 34"]
[white "Max Illingworth"]
[black "Pentala Harikrishna"]


White to move.

In this World Cup game, Black demonstrated the power of pawns and won the game despite being a piece down. I think White's defense in the game was very weak (possibly due to time pressure). I think this is the critical position,  White needs to decide what to do with the extra piece. Despite a piece down, I think this is close to winning for Black, but the computer thinks it's only slightly better for Black.

Is there a defense for White? Is there a better line than the continuation played in the game?
Despite this post being over 2 years old, the position seems to be very interesting and caught my attention. So here are my two-cents on it:

I'm rather surprised by white's follow-up moves in that game, I just don't see what is being gained! Instead, first thought that comes to my mind is to bring the h3 bishop into the game, which in fact in the actual game is left on h3 for at least 10 moves, then moved to f1 and eventually e3-Be2 is played, but in all that the light square bishop has played no role whatsoever to justify white for being up a piece. 

So let's simply focus on that and try to revive the bishop with Kf1 and Bg2. Once our bishop is in play, the trade of black's bishop for our knight will likely be in our favour as we'd still have our two pawns, and two active pieces against the single rook, whereas in the game itself, once the bishop is brought into the game, white has already lost the h2 pawn and black's pawns are already storming down the board. 

Here's an annotated diagram to study Kf1-Bg2 idea:

 [title "A different approach for white: reviving the bishop"]
 [fen "N7/P3pk1p/3p2p1/r4p2/8/4b2B/4P1KP/1R6 w - - 0 34"]

 1.Kf1 Rxa7 2.Bg2 g5 {the early g-pawn push is mainly aimed at stopping white's h-pawn from advancing and attempting to undermine black's pawn chain. If black is allowed, g4 is next.} 3.Bc6 {Important move here: stops the Ra4 - Rf4+ - Rg4 maneuver, and leaves g2 as Luft for the king thus freeing the rook from the first row, more active prospects compared to g2, and temporarily untouchable on c6 as Ra6 can be answered by Be8+ and Nc7, all while maintaining control over the important long diagonal. } g4 (3...e6 4.Rb7+ Rxb7 5.Bxb7 {and if anything the draw is well in hand, as we've kept the knight next to the opposite color bishop situation.})  4.Nb6 {hard to find an immediate plan for black} Bd4 {prophylactic vs Nd5} (4...Bxb6 5.Rxb6 {and unlike the actual game we still have the h-pawn, our bishop is in play, and our rook in time to go behind the pawns} h5 6.Kf2 h4 7.Rb8 Ra3 8.Bd7 e6 9.Rh8 {forcing h3 with all the pawns on light squares, then we just have to stop f4 and black cannot make progress.} h3 10.Rh6 f4 11.Kg1 {side-stepping g3 with check, as that would probably be losing on the spot} Ra1+ 12.Kf2 Rh1 13.Bxe6+ Kg7 14.Rh4 Rxh2+ 15.Kg1 Rxe2 16.Bxg4 h2+ 17.Kh1 Rf2 18.Rxh2 {it's worth exploring some of these lines as they're very sharp and concrete therefore highly non-trivial.}) 5.Nd5 e6 6.Nf4 Rc7 7.Ba4 {Even Rb7 looks sufficient for a draw, but requires more calculation to make sure.} d5 8.h3 {if Be3, Ng2 works which is lucky. As for the rest: we've brought all pieces into play, pinned most black pawns to light squares, and managed to trade our h pawn, and big prospects of holding this position, and even winning it if black goes wrong.}


So in summary, it seems that by bringing the bishop into play immediately, we've managed to muster up an actual defense against the pawn storm, and even create active play, thus in fact making a case for being a piece up! This seems to be far more playable than the version of the endgame that transpired in the actual game.