Pawel Sowinski vs Vahe A. Sukiasyan: game review

27.f4! The only good move here: every alternative is clearly worse.

• Attacks the knight on e5.
• Pushes a pawn towards the Black king, to pry open lines in front of it.
• The next best move, 27.exd5, would drop White's winning chances from 45% to 27% (−2.70).
• 27.f4 threatens fxe5, winning a knight.
• It threatens fxe5, winning a knight, so Black has to spend the next move on it.
• Black answers 27…Nc6, opening the line of the queen on b8 to the f4 pawn.

34…Bxg2+! The only good move here: every alternative is clearly worse.

• Takes the bishop on g2.
• The next best move, 34…Bf8, would drop Black's winning chances from 65% to 54% (−0.45).
• 34…Bxg2+ trades bishops and gives check, leaving two replies.
• Trades bishops.
• Check, and White has only two legal replies.
• White answers 35.Kxg2, taking back, leaving Black with no bishop pair.

42…Rxd3! The only good move here: every alternative is clearly worse.

• Takes the rook on d3.
• The next best move, 42…Ne3, would drop Black's winning chances from 85% to 73% (−2.76).
• 42…Rxd3 wins a pawn and trades off the attacked rook instead of losing it to Bxc3.
• Takes the rook on d3 and wins a pawn once the captures settle.
• White was threatening Bxc3, winning a rook for a piece and a pawn. The rook takes something with it instead.
• White answers 43.Rxd3, taking back.

44…Nf2+!! A real sacrifice: Black gives up material and the engine still rates it best.

• Puts the knight on f2 where it can be taken.
• White can take, but after 45.Qxf2 Qh1+ 46.Qh2 Qf1+ the engine rates it −6.55.
• Check, and White has only two legal replies.
• 44…Nf2+ gives check, leaving two replies.
• White answers 45.Qxf2, winning a knight.
• After 45.Qxf2 Qh1+ 46.Qh2 Qf1+ 47.Qg2 Qxd3 48.Qf3 Qxf3 49.Nxf3 Rc2, the queens come off and Black comes out two pawns up (−6.55).

• The idea: 44…Nf2+!! offers the knight on f2. Taking it gives Black the material back and more.
• What Black gives up: 44…Nf2+ puts the knight on f2 where it can be taken by the queen on g2. That's a knight on offer.
• If White takes the knight: 45.Qxf2 is met by 45…Qh1+. Then 46…Qf1+ gives check, and 47…Qxd3 takes the rook on d3. Black ends up a piece and a pawn ahead: Black is winning (−5.55). This is White's best try.
• Without the sacrifice: The best move without the sacrifice, 44…Qa2, is clearly weaker (−4.96 against −6.55). White answers 45.Rb3, threatening Rxb4, winning a bishop and a pawn. Black would still be winning, but far less than after 44…Nf2+.

• Both sides followed opening theory up to 6.Nc3: 11 moves in all, 6 by White and 5 by Black.
• Theory runs out after 6.Nc3: too few games between strong players reached this position to go further.