Yusupov - Spiridonov training question One of the lessons on the Chess.com site uses the Yusupov - Spiridonov match, with Black to play after 1.Nf6+:

[fen "5rk1/pb3p1p/1pr5/8/2P1p1N1/qPQ1P3/4B1PP/3R2K1 w - - 0 1"]

1.Nf6+


The "correct" move to make here is for the rook to take the knight, which is fine.

What I didn't understand was the explanation of why that is the correct move:


  Had he moved his King to h8 White would have played Rd1-a1 after which
  Black loses his Queen to a discovered check with the Knight on f6.


I can't see anyway that black would lose his queen. The knight moving will put the king in discovered check, but the only way I can see black losing his queen is if white sacrifices a rook.

What am I missing?
After the moves 1. ... Kh8 2. Ra1 from your diagram position, the black queen is attacked and the only "safe" squares it has available (where it wouldn't be immediately captured on the following move) are then c5, d6 and e7. The text you quoted is pointing out that no matter which of those the queen might move to, there is a discovered check by the knight which nabs the queen anyway:


2. ... Qc5 3. Nxe4+ (or 3. Nd7+)
2. ... Qd6 3. Nxe4+ (or 3. Ne8+)
2. ... Qe7 3. Nd5+


At best for Black in those lines, he's losing his queen for knight. Because of that, after 1. ... Kh8 2. Ra1, Black could instead bite the bullet and play 2. ... Qxa1 3. Qxa1, hoping to "only" give up queen for rook (and I think that's the line you have in mind at the end of your question). Now as it turns out, from that position Black actually has no way to avoid a further loss of rook for knight (again because of discovered check threats that still remain), and so would ultimately end up with a net loss (starting from your diagram position) of queen for knight in that line too.

[fen "5rk1/pb3p1p/1pr5/8/2P1p1N1/qPQ1P3/4B1PP/3R2K1 w - - 0 1"]

1.Nf6+ Kh8 2.Ra1 Qxa1+ (2...Qc5 3.Nxe4+) (2...Qd6 3.Nxe4+) (2...Qe7 3.Nd5+) 3.Qxa1