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| Black has just captured on e5 in Spanton (1840) - Ryan Cheung (1681), 4NCL Division 4 (Maidenhead) 2020. Who stands better, and by how much? |
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This ending from the Exchange Variation of the Spanish is rather different from most of the previous ones in this series in that the white queenside pawns are fixed on light squares, making them vulnerable to the bishop. The analysis engines Stockfish12 and Komodo12.1.1 rate the position as dead-equal.
33.f4+ Ke6 34.Nd2!?
This is probably OK, but it gives the bishop more scope, Holding the draw is easier after 34.Kd3 or 34.Ng5+.
34...Bc2
Now the knight is tied to protecting the b3 pawn, while the bishop can pressurise b3 from c2 and d1.
35.h3 Kf5
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36.Ke2?
White seems to be able to hold the balance with 36.Kf3 and 36.h4.
After 36.Kf3 Bd1+ 37.Ke3 c6 38.h4 Kg4 39.Kf2 Kh3, White has 40.Ke1 and 41.Kf2.
After 36.h4 Kg4 37.Kf2, White is again holding.
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36...g5
Missing a win with 36...h4!, eg 37.Kf2 hxg3+ 38.Kg3 Bd1 39.h4 c6, when White is in zugzwang. Alternatively, 37.gxh4 Kxf4 38.Kf2 c6, and again White is in zugzwang.
37.fxg5 Kxg5 38.Kf3 Bf5!?
Black should be OK after this, but it will require precise play. Easier is 38...Kf5, when White's winning attempt with 39.g4+!? is double-edged, eg 39...hxg4+ 40.hxg4 Ke5!? 41.Ke3 Bd1 42.g5, after which the engines give best-play as 42...Bc2 43.g6! Bxg6 44.Nf3+, when White has what seem decent drawing chances.
39.Ne4+
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39...Kg6
It seems Black had to find 39...Kh6!, when 40.g4 hxg4 41.hxg4 Bg6 42.Kf4 Kg7 43.Ke5 Kf7 holds, according to the engines.
40.g4 Bd7?
If, as in the previous note, 40...hxg4+ 41.hxg4, the bishop has to leave the h7-b1 diagonal, for example by 41...Bd7, when 42.Kf4 leaves Black with problems getting timely counterplay against the white queenside. However, it is not clear Black is lost, so this would be best.
41.gxh5+ Kh6
Not 41...Kxh5?? 42.Nf6+.
42.h4 Bh3 43.Ng3 Bd7 44.Kf4 c6 45.Ke5 Bg4 46.Kd6 Bf3 47.Kc7 b5 48.cxb5 cxb5 49.axb5 c4 50.bxc4 a4 51.Nf5+ Kxh5 52.Nd4 Bd1
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53.b6?
This is winning, but gives Black unnecessary chances. Simpler is 53.Nc6 a3 54.Nb4 Bb3 55.b6 a2 56.Nxa2 Bxa2 57.b7 etc.
53...a3 54.b7 a2 55.b8=Q a1=Q 56.Qh8+ Kg4 57.Qg7+?
Best, according to the engines, is 57.c5.
57...Kh3
Not 57...Kxh4?? 58.Nf5+ and 59.Qxa1.
58.Qd7 Bg4 59.Qd5 Kxh4
White's advantage is down to one pawn, which means the game will be drawn if Black can give up his bishop for the pawn. In fact the position is already a tablebase draw.
60.Nb5 Qg7+ 61.Kb6 Qf6+ 62.Nb6 Qb2+ 63.Kc5 Qa3+ 64.Kd4 Qb2+ 65.Kc5 Qa3+ 66.Kb6 Bf3 67.Qd4+ Kh3 68.Nb5 Qa8 69.Qd7+ Kg2 70.Qc7 Qf8 71.c5 Qf6+ 72.Qd6
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72...Qg5+
This is still a tablebase draw (at almost every move Black has had a large choice of moves that kept the draw), but perhaps simpler is 72...Qxd6+ 73.cxd6 Bg4.
73.Nd4 Bg4!?
During the game I thought the bishop should stay on the long diagonal, but the text is also good enough to draw.
74.c6
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74...Qc1?
74...Qe3 and 74...Qd2 draw.
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75.Qd5+!
The only winning move*, although Komodo12.1.1 prefers 75.c7.
75...Kh3 76.c7 Qb2+
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77.Nb5
Now the game is a tablebase draw again - only 77.Qb3+! wins.
77...Qf2+ 78.Qd4
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78...Qf5?
Black had three drawing moves: 78...Qxd4+, 78...Kg3 and 78...Kg2.
79.Nd6
Also winning is 79.Nc3.
79...Qb1+ 80.Ka7 Qa2+ 81.Kb8 Qb3+
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82.Nb7?
Only 82.Ka8 and 82.Ka7 win.
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82...Qg3?
Six moves draw: 82...Qg8+, 82...Qb5, 82...Qb1, 82...Kg3, 82...Bf5 and 82...Qf3.
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83.Qh8+?
There are two winning moves: 83.Nc5 and 83.Nd6.
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83...Kg2?
83...Qh4 draws.
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84.Qb2+?
Again there are two winning moves: 84.Qd4 and 84.Nc5.
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84...Kg1?
Two moves draw: 84...Kh3 and 84...Qf2.
85.Qb6+ Kg2
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86.Nd6
Only 86.Qd4! wins.
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86...Qh3?
Black draws with 86...f4, 86...e5 or 86...d3.
87.Qb2+ Kg1 88.Ne4!?
I decided my best practical chance of winning lay with attacking the black king.
88...Qf3 89.Qd4+ Kg2 90.Qd2+ Kg1 91.Qb4 Qf4 92.Qb1+ Kg2
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93.Qb2+
The only winning move.
93...Kf3
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94.Nf6!
Again an only-move.
94...Bf5
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95.Qc3+?
There are three winning moves: 95.Qb3+, 95.Qb7+ and 95.Qb5.
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95...Kf2?
RC has been studiously avoiding an exchange of queens, but once again allowing it, this time by 95...Qe3, is the correct play.
96.Nd5 Qf3 97.Qd2+ Kg3 98.Qe1+ Kg4?
Every move loses, but this makes it relatively easy by allowing White to eliminate the minor pieces and so remove the bishop-takes-pawn drawing resource.
99.Ne3+ Kf4 100.Nxf5 Qb3+ 101.Kc8 Kxf5 102.Qe8 Qb6 103.Qe7 Kf4 104.Kd7 Qb5+ 105.Kd8 Qd5+ 106.Ke8 Qa8+ 107.Kf7 Qd5+ 108.Kg6 Qg2+ 109.Kh7 Qh3+ 110.Kg8 Qg4+ 111.Kf8 Qc8+ 112.Kf7 Kf3
Not 112...Qf5+? 113.Qf6.
The game finished:
113.Qd8 Qb7 114.Qd7 Qb3+ 115.Kf8 Qb4+ 116.Qe7 Qb7 117.Kg7 Kg3 118.Qe5+ Kf3 119.Kg6 Kg2 120.Kg5 Qc8 121.Qe4+ Kg3 122.Qf4+ Kh3 123.Qh4+ 1-0
*Note that this and the following tablebase evaluations do not take into account the 50-move rule - they merely show whether a checkmate is possible in any number of moves with perfect play by both sides.
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