Spanton (1936 ECF/1977 Fide) - Andy Trevelyan (1920 ECF/1812 Fide)
King's Indian Sämisch
1.d4 Nf6 2.c4 g6 3.Nc3 Bg7 4.e4 d6 5.f3 0-0 6.Bg5!?
This is the second-most popular continuation in ChessBase's 2025 Mega database, but a long way behind 6.Be3.
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| How should Black respond? |
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6...Nbd7
The main line in Mega25 runs 6...c5 7.d5 e6 8.Qd2 exd5 9.cxd5 a6 10.a4 Re8 11.Nge2 Nbd7 12.Ng3 Qa5, when Stockfish17 and Dragon1 give White a slight edge.
7.Qd2 Re8!? 8.Nh3!? e5!?
The engines strongly dislike this, preferring 8...Nf8 9.Nf2 Ne6!?
9.d5 Nf8 10.Nf2 Bd7 11.Be2 h5!?
Apparently a novelty, and preferred by the engines over the known 11...Rc8.
12.h4!? N8h7
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| How should White proceed? |
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13.Be3!
The engines much prefer this over 13.Bh6 Bxh6! 14.Qxh6, after which they coolly continue with 14...c6!?, the point being Black has swopped off his bad bishop, and does not need to worry about the white queen, which looks aggressive but lacks support.
Both moves, according to the engines, are better than leaving White's dark-square bishop where it is, eg 13.g4 Nxg5 14.hxg5 Nh7 15.gxh5 Qxg5, after which the danger to Black's kingside seems over.
13...Qc8!? 14.0-0-0
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| Now both sides have castled, how would you assess the position? |
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Material is equal, and positions with opposite-side castling are difficult to judge, but White has more space, and White seems better placed to attack on the kingside than Black is on the queenside. The engines reckon White has a positionally won game.
14...a6 15.Kb1 Rb8 16.Rdg1 b5 17.c5 b4 18.Ncd1 dxc5 19.Bxc5 a5 20.g4 Bb5 21.Nd3 Nd7
The engines suggest 21...c6.
22.Be3
This looks natural, but the engines reckon White can sacrifice a piece with 22.gxh5!? Bxd3+ 23.Qxd3!? Nxc5 24.Qc4, followed by 25.hxg6.
22...Nhf6 23.Bh6!?
This is playable, now Black is no longer able to reply with ...Bxh6 as Qxh6 would leave White geared up for a strong attack.
23...c5 24.dxc6!?
The engines do not like this, reckoning White should keep lines closed on the queenside for as long as possible.
24...Qxc6 25.Bxg7 Kxg7 26.Qg5
The engines prefer 26.gxh5 Nxh5 27.Ne3, but reckon chances are equal.
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| What should Black play? |
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26...Rbc8
26...Rbc8
The sacrifice 26...Nxe4? 27.fxe4 Qxe4 can be met by 28.Qe3, but the engines like 26...Qd6 and 26...b3, albeit Stockfish17 is much keener than Dragon1.
27.Ne3??
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| Black to play and win |
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27...Rh8??
Missing that 27...Nh7 wins material as 28.Nf5+ Kh8 leaves White with two pieces en prise.
28.Rc1 Qc6 29.Rxc8
Even stronger is the engines' 29.Nf5+ Kf8 30.Nxb4!, eg 30...axb4 31.Bxb5 Qa8 (31...Qxb5 32.Rc8+ and mates) 32.Bxd7 Nxd7 33.Qe7+ Kg8 34.Rxc8+ Qxc8 35.Nd6 etc.
29...Rxc8
Not 29...Bxd3+ 30.Bxd3 Qxd3+? 31.Rc2, while 29...Qxc8 30.Rc1 Bxd3+ 31.Bxd3 Qb7 32.Bc4 is also very good for White.
30.Nxb4?
The same idea as in the note to White's 29th move, but it is no longer strong. Instead 30.Nf5+ wins, eg 30...Kf8 31.Qh6+ Ke8 32.Qh8+ Nf8 and now 33.Nxb4!, for example 33...axb4 34.Bxb5+ Qxb5 35.Nd6+ etc. Probably slightly better is 30...Kg8!?, but in addition to 31.Ne7+ Kh7 32.Nxb4! the engines fairly quickly find 31.Nf4+!, eg 31...exf4 32.Ne7+ Kg7 33.Bxb5 Qb7 34.Nf5+ Kg8 35.Nd6 Qb8 36.Nxc8.
30...axb4 31.Bxb5 Qxb5 32.Nf5+ Kg8
Not 32...Kf8?? 33.Qh6 Ke8 34.Nd6+ and 35.Nxb5.
33.Ne7+ Kf8?
The engines reckon Black has enough compensation for the exchange after 33...Kg7 34.Nxc8+ Qd3+ 35.Ka1 Qxf3.
34.Nxc8 Qd3+ 35.Ka1 Qxf3 36.Rc1
White is winning because, unlike in the previous note, the white queen has a check on h6.
36...hxg4 37.Qh6+ Ke8 38.Qd2?
White has a win with 38.Qh8+ Nf8 39.Nb6!, eg 39...Ke7 40.Nd5+! Nxd5 41.Qxe5+ Kd8 42.exd5 etc.
38...Qf4 39.Nd6+ Kf8 40.Qc2 g3 41.Qc4
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| Black to play and draw |
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41...Ng4
This looks natural and forced, but the engines' 41...Kg7!! draws, the point being that after 42.Qxf7+ Kh6 White has nothing better than 43.Qc4, when Black's passed g pawn gives sufficient counterplay.
42.Rf1 Nf2
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| How should White continue? |
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43.Qxb4?
This loses.
There seem to be several drawing lines, including 43.Qc8+ Ke7! (43...Kg7? 44.Qxd7 g2 45.Rg1) 44.Nb7! g2 45.Qd8+ Ke6 46.Qe8+ Kf6 47.Qh8+ with perpetual check, and 43.Rg1 Kg7! 44.a4!? bxa3 45.bxa3 Nh3 46.Rg2 Nf2 47.Rg1 etc.
However, the best try is probably 43.h5!?, as it is tricky to meet, eg 43...gxh5? (this is the engines' choice at first) 44.Qc8+ Ke7 45.Nf5+ (this is possible now Black's g6 pawn has been diverted) Kf6 46.Qxd7 g2 47.Qd6+ Kg5 48.Qd8+ Kg6 49.Qg8+ Kf6 50.Qg7+ Ke6 51.Qxg2 wins for White. Better is 43...g2, when 44.Rg1 Qf3 45.hxg6 fxg6 46.Qc7 Kg8 47.Qxd7 Nh3 seems to hold, and 43...Kg7 may also be good enough for a draw.
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| Black to play and win |
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43...Kg7
Winning is 43...g2! as White has no useful discovered check, and, according to the engines, has nothing better than 44.Rb1, when 44...Nd3! wins, eg 45.Qc4 Qf1! 46.Qf7+!? Qxf7 47.Nxf7 Kxf7, after which the knights and Black's pawn on the seventh are too much for the rook to handle. If 45.Qb3, then 45...N7c5 brings another piece decisively into the attack, eg 46.Qd1 Qf2 47.Qg1 Qd2 48.Nc4 Qb4 49.Na3 Qxe4 with what the engines reckon is an overwhelming position.
44.Ne8+ Kh6
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| White to play and draw |
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45.Qe1?
The engines agree 45.Qe7! draws, their main line running 45...g2 46.Qg5+ Qxg5 47.hxg5+ Kxg5 48.Rg1 Kf4 49.Rxg2 Nxe4, when Black's active king and extra pawn seem to provide full compensation for the exchange.
Stockfish17 reckons 45.Qd6!? also draws. but Dragon1 claims it loses. After Dragon1's 45...Nxe4, Stockfish17 gives 46.Qd3, when Dragon1's 'winning' 46...Ndc5?! runs into 47.Rxf4 Nxd3 48.Rxe4 f5 49.Re3 g2 50.Rg3, after which 50...Ne1 gives complete equality, Dragon1 'admits', but it loses for Black, according to Stockfish17. However the engines agree 46...Nec5!? draws. Having gone through this analysis, I took the engines back to the position after 45.Qd6!?, when Dragon1 changes to agreeing the position is drawn, but Stockfish17 at first reckons 45...g2!? gives Black a slight edge, although it fairly soon reverts to calling the position equal. So it seems 45.Qd6!?, like 45.Qe7!, draws, but the line is very complicated, even for top engines.
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| Black to play and win ... or lose |
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45...Qxe4??
This turns a win into a loss.
White has no good answer to activating the 'reserve' knight with 45...Nc5, eg 46.Nd6 Ncd3 47.Qb1 Kh5! 48.a4 Kxh4 49.a5 Nb4 50.Nc4 g2 51.Rg1 Kh3 52.b3 Nfd3 53.Nb2 Nxb2 54.Kxb2 Qd2+ 55.Ka3 Nc2+ 56.Kb2 Nd4+ etc.
The engines reckon the immediate 45...Kh5!? also wins.
46.Qd2+ Qf4 47.Qxd7 g2 48.Rg1 Nh3??
Missing a backward queen move in time trouble, but after the better 48...Ng4, both 49.Nf6 and 49.a4 win, according to the engines.
49.Qxh3 Qf2 50.Qxg2 1-0
At move 7, White can play dxc5 and then Bxc5 winning the pawn. It may look as if 6. .. c5 is just a blunder, but there seems adequate play in the ending. As a consequence 7. d5 is often played, leading to a Modern Benoni like position.
ReplyDeleteRdC
Correction It's only after 6 Be3 that the pawn sacrifice is offered.
ReplyDeleteRdC
6.Be3 was Sämisch's original idea, and it is still the commonest continuation, but, judging by his games in Mega25, he came to prefer 6.Bg5!?
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