NikoTheodorou vs Sina-Movahed: game review

34…Qa8! The only good move here: every alternative is clearly worse.

• Moving away uncovers the rook on d8, which now hits the rook on d1.
• Moves the attacked queen to safety.
• The next best move, 34…Qxd1, would drop Black's winning chances from 49% to 13% (+5.27).
• 34…Qa8 gets the queen out of the way of Rxd5.
• White was threatening Rxd5, winning the queen for a rook. The queen steps away.
• White answers 35.a4.

35…Nc6 is a blunder: Black's winning chances go from 51% to 0%.

• White answers 36.Bd3.
• Better was 35…Qc8 (−0.16).

Better: 35…Qc8 threatens …Qxf5, winning the queen, and stops Bxe5. After 36.Qxc8 Rxc8 37.Bxe5 Bxe5 38.Bc4 Rc7, the queens come off (−0.16).

36.Bd3!! A real sacrifice: White gives up material and the engine still rates it best.

• Leaves the bishop on d4 where it can be taken.
• Taking is too dangerous: Black's best reply is 36…Kg8 37.Qh7+ Kf8 38.Qxg7+ instead (the engine rates it +30.65).
• 36.Bd3 threatens Qh7#, with mate in 1, and stops …Nxd4.
• It threatens Qh7#, with mate in 1, so Black has to spend the next move on it.
• Black was threatening …Nxd4, winning a rook for a pawn. Bd3 takes care of it.
• The engine's plan continues with Qh7+ and Qxg7+: this move is the first step.

• The idea: 36.Bd3!! leaves the bishop on d4 hanging. Taking it leads to mate.
• What White gives up: The bishop on d4 is attacked by the knight on c6, the bishop on g7 and the rook on d8, and 36.Bd3 doesn't save it. That's a bishop on offer.
• What it does instead: It threatens Qh7# and mate.
• If Black takes the bishop: 36…Rxd4 is met by 37.Qh7#, and it's mate.
• Black's best try: Black's best is to leave the bishop alone and play 36…Kg8. White answers 37.Qh7+. Then 38.Qxg7+ gives check, and 39.Qf6+ gives check. White ends up a piece and a pawn ahead: White is winning (+30.65).
• Why not save the bishop first?: Saving it with 36.Bxg7+, the best way to do that, is clearly weaker (+4.25 against +30.65). Black answers 36…Kxg7, taking the bishop on g7 and threatening …Rxd1+, with a dangerous check. White would still be winning, but far less than after 36.Bd3.

• Both sides followed opening theory up to 11.Nc2: 21 moves in all, 11 by White and 10 by Black.
• Theory runs out after 11.Nc2: too few games between strong players reached this position to go further.