Surya Shekhar Ganguly vs Murali Karthikeyan: game review

31.g3 is a mistake: White's winning chances go from 42% to 32%.

• Black answers 31…Nxe5, which takes the pawn on e5.
• After Nxe5, Black wins 1 point of material within 2 moves.
• Better was 31.Bb3 (−0.84).

Better: 31.Bb3 prepares Rd1 and Rc1. After 31…Nxe5 32.Rd1 Nc6 33.Rc1 Kf8 34.Kf1, White is a pawn down (−0.84).

31…Nxe5!! A real sacrifice: Black gives up material and the engine still rates it best.

• Leaves the knight on f4 where it can be taken.
• Taking is too dangerous: White's best reply is 32.Bd1 Nd5 33.Be2 Rc1+ instead (the engine rates it −1.96).
• Takes the pawn on e5.
• Centralises the knight on e5, where it reaches the most squares.
• 31…Nxe5 wins a pawn and threatens …Nf3+, winning a rook, picking it up with 33…Nxd2+.
• Takes the e5 pawn and wins a pawn once the captures settle.

• The idea: 31…Nxe5!! ignores the attack on the knight on f4 and takes the e5 pawn first. Taking the knight gives Black the material back and more.
• What Black gives up: The knight on f4 is attacked by the g3 pawn, and 31…Nxe5 doesn't save it. That's a knight on offer.
• If White takes the knight: 32.gxf4 is met by 32…Nf3+, and the knight on e5 gets away. Then 33…Nxd2+ gives check, and 34…Rxc2 takes the bishop on c2. Black ends up a piece ahead: Black is winning (−6.21).
• White's best try: White's best is to leave the knight alone and play 32.Bd1. Black answers 32…Nd5, and the knight on f4 gets away, planting the knight on the d5 outpost. Then 33…Rc1+ gives check, and 34…Rc2 threatens …Rxe2, winning a bishop. Black ends up a pawn ahead: Black is clearly better (−1.96).
• Why not save the knight first?: Saving it with 31…Nd5, the best way to do that, is clearly weaker (+0.26 against −1.96). White answers 32.f4, threatening Nd6, winning a knight. That would leave Black level.

32…Nd5! The only good move here: every alternative is clearly worse.

• Plants the knight on d5: a pawn defends it and no enemy pawn can chase it away.
• Moves the attacked knight to safety.
• The next best move, 32…Nc4, would drop Black's winning chances from 69% to 57% (−0.79).
• 32…Nd5 gets the knight out of the way of gxf4.
• White was threatening gxf4, winning a knight. The knight steps away.
• White answers 33.Be2, leaving Black with a king with pawns missing from its shelter.

• Both sides followed opening theory up to 11…cxd4: 22 moves in all, 11 by White and 11 by Black.
• Theory runs out after 11…cxd4: too few games between strong players reached this position to go further.