ACO World Amateur Game Three

Spanton (1804) - Peter Carlsten (1907)

Sicilian Bb5(+)

1.e4 c5 2.Nf3 Nc6 3.Bb5 g6 4.c3 Bg7 5.d4 cxd4 6.cxd4 Qb6

Black attacks the undefended bishop as well as adding another piece to the attack on d4 - how should White respond?

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7.Nc3!?

Defending the bishop but offering the d4 pawn. After 7.Bxc6 dxc6 (7...bxc6 is also popular) the game is equal, according to Stockfish15.1 and Komodo14.1.

7...Nxd4!?

This is the main move in ChessBase's 2023 Mega database, but White gets great compensation.

8.Nd5 Nxf3+ 9.Qxf3 Qd6!?

Not 9...Qxb5?? 10.Nc7+ etc. The engines reckon the text is best. Most popular in Mega23 is 9...Qd8?!, but then 10.Bf4 is very strong as 10...e5 can be met by 11.Qc3.

10.Bd2

Threatening Bb4.

10...Bxb2!?

Komodo14.1 likes this and 10...e6, although Stockfish15.1 prefers 10...Nf6. After the latter, best play, according to the engines, goes 11.Bb4 Qe5 12.Bc3!? Qd6 13.0-0-0 with what they reckon is a winning lead in development.

11.Rb1

Even stronger may be Stockfish15.1's 11.0-0, eg 11...Bxa1 12.Rxa1 Nf6 13.Bb4 Qe5 14.Bc3!? Qd6 15.Nxe7!?

11...e6?!

The engines give 11...Nf6!? 12.Rxb1 Nxd5 13.0-0, awarding White the upper hand despite being two pawns down, but not 13.exd5? Qe5+ and 14...Qxb2.

12.Rxb2 exd5 13.0-0 Qe5

How should White proceed?

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14.exd5!? Qxb2

Accepting the rook is Black's only chance.

15.Qe2+?

Protecting both white bishops and ensuring the king cannot move as that would lose the black queen (after Bh6+ or Ba5+). However 15.Re1+ is stronger despite leaving both white bishops unprotected, eg 15...Kf8 16.Qe3 a6 (this is best, according to the engines, not least because 16...Qxb5? fails to the spectacular 17.Qh6+! Nxh6 18.Bh6+ Kg8 19.Re8#) 17.Bc3 leads to mate unless Black gives up the queen with 17...Qxc3.

15...Ne7 16.d6 0-0 17.dxe7 Re8 18.Re1 a6 19.Bc4

With the winning threat, among others, of 20.Bxf7+!?

19...Qf6?

This prevents the bishop sac, but best seems to be 19...d5! 20.Bxd5 Be6, after which the engines reckon White does not have enough for the exchange.

White to play and win

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20.Qe3!

There is no defence to this quiet move.

20...d5

This is the best try, according to the engines.

21.Bxd5 Be6 22.Bc3 Qf5

Or 22...Qxe7 23.Qd4 f6 24.Rxe6 etc.

23.Qh6 1-0