Read Samadov vs Erdem Khubukshanov: game review

25…Nc8 is a blunder: Black's winning chances go from 43% to 19%.

• White answers 26.Rxc6, which takes the pawn on c6.
• After Rxc6, White wins 1 point of material within 4 moves.
• Better was 25…Nf7 (+0.80): moving away uncovers the queen on e7, which now hits the queen on c5.

Better: 25…Nf7 wins a knight for two pawns, picking it up with 26…cxd5, and threatens …Qxc5, winning a knight. After 26.Nxd5 cxd5 27.Qxd5 g4 28.Nh4 Bxh4 29.gxh4 Kh8 30.Bxf5 Bxf5 31.Qxf5 Qxh4, the bishops are traded and Black comes out a pawn up (+0.80).

26.Rxc6!! A real sacrifice: White gives up material and the engine still rates it best.

• Puts the rook on c6 where it can be taken.
• Taking is too dangerous: Black's best reply is 26…Qxc5 27.Rxc5 Be7 28.Rc7 instead (the engine rates it +3.80).
• Takes the pawn on c6.
• Lines up rook and queen on the c-file, so the two pieces push in the same direction.
• 26.Rxc6 wins a pawn.
• Takes the c6 pawn and wins a pawn once the captures settle.

• The idea: 26.Rxc6!! offers the rook on c6. Taking it gives White the material back and more.
• What White gives up: 26.Rxc6 puts the rook on c6 where it can be taken by the bishop on d7. That's a whole rook on offer.
• If Black takes the rook: 26…Bxc6 is met by 27.Qxc6, taking the bishop on c6 and threatening Qxa8, winning a rook and a pawn. Then 28.Nxd5 takes the d5 pawn, and 29.Nc7 threatens Nxe6, winning the queen for a knight. White ends up two pawns ahead: White is winning (+4.18).
• Black's best try: Black's best is to leave the rook alone and play 26…Qxc5. White answers 27.Rxc5, taking the queen on c5 and threatening Nxd5, winning a pawn. Then 28.Rc7 threatens Rxd7, winning a bishop, and 29.Nxd5 takes the d5 pawn. White ends up a pawn ahead: White is winning (+3.80).
• Without the sacrifice: The best move without the sacrifice, 26.Qxe7, is clearly weaker (+1.15 against +3.80). Black answers 26…Bxe7, taking the queen on e7 and threatening …Nxb6, winning a rook. That would leave White a little better.

30…Nf7 is a mistake: Black's winning chances go from 15% to 0%. It allows mate in 3.

• White answers 31.Qxf5, which takes the pawn on f5.
• After Qxf5, White wins 1 point of material within 2 moves.
• Better was 30…Qxd7 (+4.80), which takes the queen on d7.

Better: 30…Qxd7 trades queens. After 31.Nxd7 Bg7 32.Ne7+ Kf7 33.Nxc8 Rxc8 34.Nc5, Black is two pawns down (+4.80).

• Both sides followed opening theory up to 8.Bf4: 15 moves in all, 8 by White and 7 by Black.
• Theory runs out after 8.Bf4: too few games between strong players reached this position to go further.