A Shot In The Arm

HAD my first covid vaccination today, shortly after 3pm.

It was the cheapo Astra-Zeneca version.

There have been no discernible side-effects in the first 55 minutes or so ...

My second shot is due on May 16.

Knight v Bishop (part 45)

White has just captured on e5 in Andrew C Waters (154) - Spanton (170), Kent League 140 Average 2020. Who stands better, and by how much?

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Unbalanced pawn-majorities favour a bishop over a knight. In addition Black has an isolated d pawn. True, it is passed, but then so is White's protectable e pawn. The analysis engines Stockfish12 and Komodo12.1.1 give White a slight edge.

24...Nc4 25.f4!?

The engines prefer the less-committal 25.Kd3. My engines at the time of this game, Stockfish10 and Komodo10, preferred 25.e6!?, meeting 25....Kf8 with 26.Bg5!? My more-modern engines reckon the continuation 26...Nxb2 27.Ke3 h6 28.Bf6 gives White compensation for the sacrificed pawn, but no more.

25...Kf7

Stockfish12 strongly prefers 25...Na5!?

26.Kd3 Ke6 27.Kd4 Nb6 28.b3 Nc8 29.Ba3 Nb6

The engines prefer 29...b6!? but reckon White is on top.

30.Bb4 Nd7 31.Bd6 Nb6 32.a4 Nc8 33.Ba3 b6 34.Bb4 a5 35.Ba3?

The engines give White a large advantage after 35.Bd2!?, the point being to target the black queenside pawns fixed on dark squares, eg 35...Ne7 36.Be3 Nc8 (36...Nc6? 37.Kd3 leaves Black unable to defend b6) 37.Kc3 Kd7 38.Bf2 Ke6 39.b4 axb4+ 40.Kxb4 Kd7 41.Kb5 Kc7 42.Ka6 Kc6 43.e6! Kc7 44.Bd4 Kc6 45.Be5 h6 46.Bd4 Kc7 47.Bc3 Kc6 48.Be5 g5 49.fxg5 hxg5 50.Bf6 g4 51.h4 etc. This is a long line, but Black is very restricted throughout and must succumb eventually.

Clearly the queenside pawns are the direct cause of Black's troubles, but the moves 33...b6 and 34...a5 are quite liked by the engines, showing Black has major problems whatever he plays. It seems the diagrammed position is much more favourable for White in the long term than the engines realise.

35...Na7

Black equalises because it is possible to play ...Nc6+, driving away the white king, without dropping the b6 pawn.

36.Bd6

Or 31.Bc1 Nc6+ 32.Kc3 Kd7 33.Be3 Kc7, and if 34.e6!? then 34...Kd6 35.Bxb6 Kxe6 with equality.

36...Nc6+ 37.Kc3 Kd7

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38.g4?

This turns a draw into a loss by allowing Black to create a passed h pawn.

38...fxg4 39.hxg4 h5 40.gxh5 gxh5 41.f5

Also no good is 41.Kd2 h4 42.Ke1 d4 43.Ba3 d3 44.Bc1 h3 45.Kf2 Nd4 etc.

41...h4 42.Bf8

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42...h3?

Turning a win into a draw. The patient 42...Nxe5 and the aggressive 42...d4+ win easily.

43.e6+

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43...Kc7!

Other moves lose, eg 43...Ke8 44.Bd6 Nd8 45.Kd4 etc.

44.Bh6

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44...h2?

Turning a draw into a loss.

The game finished:

45.Bf4+ Kd8 46.Bxh2 Ke7 47.Bg3 Kf6 48.Bh4+ Kxf5 49.e7 Nxe7 50.Bxe7 Ke5 1-0

Knight v Bishop (part 44)

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.

Knight v Bishop (part 43)

White has just captured on e3 in Spanton (1951) - Rohilla Shivika (1744), Hastings 2019-20. Who stands better, and by how much?

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This is another ending from an Exchange Variation of the Spanish. White has much-the-better pawn-structure, but Black has bishop-v-knight on a relatively open board with rival pawn-majorities. My experience of such positions tells me White has the upper hand, but Stockfish12 reckons White only has a slight edge, while Komodo12.1.1 rates the position as equal.

20...Kf7 21.Kd2 Ke6 22.f4 c5 23.g3 b5 24.c3 c4!?

This is Komodo12.1.1's choice, but the more pawns Black puts on light squares the weaker her dark squares become.

25.Ng4 Bf5 26.Nf2 h5 27.g4 hxg4

The engines prefer 27...Bb1 28.a3 h4!? This has the merit of fixing the white h pawn, but the black one will be hard to defend in the long run.

28.hxg4 Bb1 29.a3 Kd5 30.Ke3 Bc2 31.Nh3 Bd1 32.Nf2 Bc2 33.Kf3 g6!?

This is Komodo12.1.1's choice. At first it is strongly disliked by Stockfish12, but later comes to be that engine's top choice too.

34.Kg3 Ke6

By now Stockfish12 reckons White is winning, while Komodo12.1.1 gives White the upper hand (+.77), all without at any point coming up with a different plan for Black, apart from the questionable suggestion at move 27. 

35.Kh4 Kf6 36.Nh3 Be4 37.Ng5 Bd5 38.Kg3 a5 39.Nf3 c6 40.Ne5

Even stronger, according to the engines, is 40.g5+ Ke7 (40...Kf5? loses a pawn to 41.Nh4+) 41.f5! gxf5 42.Nd4 etc.

40...a4 41.Kf2 Bh1 42.Ke3 Bd5

Not 42...c5? 43.Nd7+.

43.Nf3 Ke6 44.Nh2 Bg2 45.Kd4 Kf6 46.Ke3

Not 46.Kc5? g5, when the engines agree Black has fully equalised. However, from a general view, this type of position is much easier for White to play. The bishop only has one target, the g4 pawn, and the black king cannot penetrate White's position. Meanwhile White can try multiple feints and thrusts until one works.

46...Ke6 47.Nf3 Kd5

The engines prefer 47...Kf7, but White is winning, eg 48.g5 Kg7 49.Ne5 Bd5 50.Kd4.

48.Ne5 Be4

Or 48...g5 49.Ng6 Bh3 (49...gxf4+? 50.Nxf4+) 50.Kf3.

49.Nxc6! Bc2? 50.Nd4?

50.Nb4+ ends the game immediately.

50....Bd1 51.g5 Kc5 52.Ke4 Bg4 53.Ke5 Bd7 54.Ne6+ Kc6 55.Nf8 Bf5 56.Kf6 Kd5 57.Nxg6 Ke4 58.Ne7 1-0

Knight v Bishop (part 42)

White has just captured on e3 in Spanton (1934) - Andre Nicolas Heidel (2178), Malta (Buġibba) 2019. Who stands better, and by how much? 

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The position is dead-equal, according to the analysis engines Stockfish12 and Komodo12.1.1.

33...b5 34.e4 Ke6

34...dxe4+? spends a tempo giving White a protected passed pawn while helping the white king to advance.

However the engines prefer 34...Ne7!? 35.Bxe7 Kxe7 36.exd5 Kd6 37.Ke4 a4 38.a3 Ke7, which they reckon is dead-equal despite White's extra pawn.

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35.a4?

The right idea, but the wrong move-order. Correct is 35.exd5+ Kxd5 36.a4! bxa4 37.c4+ with advantage.

35...dxe4+ 36.Kxe4 f5+

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37.Kf4?

Correct is 37.gxf5+ gxf5+ 38.Ke3! bxa4 39.Ba3 with approximate equality. Note that 38.Kf4? loses to 38...Ne7, eg 39.Bxe7 Kxe7 40.Ke3 (or 40.axb5 a4 41.b6 Kd7 etc) bxa4, when Black queens either the f5 or a4 pawn.

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37...bxa4?

Winning is 37...fxg4 38.hxg4 bxa4, eg 39.c4 Ne7 40.Bg7 Kf7 41.Be5 Nc6 42.Bh8 a3 43.d5 Nb4 44.Ke5 Ke7 45.Bf6+ Kd7 46.c5 a2 47.c6+ Kc8 48.Ke6 h5 49.gxh5 gxh5 50.Be5 h4 51.c7 Nxd5! 52.Kxd5 h3 etc. There are many plausible alternatives, but Black is winning in all of them, according to the engines, whereas the text restores dead-equality.

38.gxf5+ gxf5 39.Ba3 Ne7 40.c4 Ng6+ 41.Kf3 Kd7 42.Ke3 Ne7 43.d5 Ng6 44.c5

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44...Ne5!?

This active-looking move is probably good enough to hold the draw. The engines give 44...f4+ 45.Ke4 f3! 46.Kxf3 Ne5+ 47.Ke4 Nc4 48.c6+ Kc7 49.Bc5 a3 50.Kd3 Ne5+ 51.Kc2 a2! 52.Bd4 (52.Kb2?? Nd3+) Nc4 53.Kd3 Nd6, with the verdict still dead-equality.

45.Kd4 Nf3+

This is best, according to the engines.

46.Kd4

More interesting is 46.Kc3!?, as the next note explains.

46...f4?

Best, according to the engines, is 46...Ne5+, after which White 47.Kd4 (47.Kb5 f4) Nf3+ 48.Kc3!? Ne5 49.c6+ seems to be a draw after 49...Nxc6! 50.dxc6+ Kxc6, the engines' main line running 51.Kd4 Kb5 52.Bd6 Kc6 53.Bf8 Kb5 54.h4 f4! 55.h5 f3 56.Ke3 Kc4 57.Kxf3 Kb3 58.Bg7 a3 59.Kf4 a2 60.Kg5 Kc2 61.Kh6 Kb1 62.Kxh7 a4 63.h6 a3 64.Kg8 a1=Q 65.Bxa1 Kxa1 66.h7 Kb1 67.h8=Q a2 etc.

47.c6+ Kc7 48.Kc5 Ne5 49.d6+ Kc8 50.Bb2!?

A deliberate piece sacrifice, but not the only way to win.

50...Nd3+

50...Nd7+!? 51.Kd5! Nb8 52.d7+!? Nxd7 53.cxd7+ Kxd7 54.Ke4 is a simple win for White.

51.Kb6 Nxb2 52.d7+ Kd8 53.Kb7 a3 54.c7+ Kxd7 55.c8=Q+ Kd6 56.Qf8+ Kd5 57.Qxa3

The game finished:

57...Nc4 58.Qf3+ Ke5 59.Kc6 Ne3 60.Kb5 Nf5 61.Kxa5 Nd4 62.Qh5+ Ke4 63.Qxh7+ Ke3 64.Qe7+ Kd3 65.Qe1 f3 66.h4 Ne2 67.h5 Ke3 68.h6 f2 69.Qxf2+ Kxf2 70.h7 1-0

Knight v Bishop (part 41)

Black has just captured on d8 in Spanton (171) - Claudio Moni (-), Summer League 150 Average (Battersea) 2019. Who stands better, and by how much?

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Black has doubled f pawns, and White has the better minor piece for working with rival pawn-majorities. Stockfish12 reckons White has the upper hand (+.76), but Komodo12.1.1 gives White just a slight edge.

27.f3 Nc6 28.Bc3 b5

The engines reckon 28...f4!? and 28...Ke6!? equalise.

29.Kf2

The engines want White to play 29.f4!?, which I think I did not seriously consider because it gives Black the e4 square for his knight, but perhaps I overrated that factor.

29...Ke6

Again the engines reckon Black equalises with ...f4!?

30.Ke3 g5 31.Bd4 a6

Black has equalised, according to the engines.

Note that 31...Nxd4?? is a horrible blunder as the pawn-ending is lost for Black.

32.a3 Ne7 33.Kd3 Nd5!?

This looks like a good square for the knight, but the engines prefer kingside play with 33...Ng6 or 33...h5.

34.Be3 h5 35.b3

CM offered a draw.

35...Ke5 36.c3 g4!?

This comes to be Stockfish12's choice, although it later switches between the text and 36...h4. Komodo12.1.1 prefers 36...Ne7.

37.a4 Kd6 38.axb5 axb5 39.c4 bxc4+ 40.bxc4 f4?

This loses a pawn. The engines suggest 40...Ne7 or 40...Nb4+.

The game finished:

41.Bd2 Nb6 42.Bxf4+ Kc6 43.fxg4 hxg4 44.Kd4 Nd7 45.h4 gxh3 46.gxh3 Nf8 47.Be3 Ne6+ 48.Ke4 Nc5+? 49.Bxc5 Kxc5 50.h4 1-0

Knight v Bishop (part 40)

Black has just captured on d8 in Spanton (171) - Gergely Kiss (207), Pimlico Summer 2019. Who stands better, and by how much?

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This is another ending arising from the Exchange Variation of the Spanish. The analysis engines Stockfish12 and Komodo11.01 reckon White is winning.

33.b4

This makes it very difficult for Black to activate his pawn-majority.

33...Ke7 34.Ke3 Kd6

KG offered a draw.

35.Kd4 Be2 36.Nc3 Bf3 37.a4 bxa4 38.Nxa4 Bd1 39.Nc5 Bf3 40.Nb7+ Ke6 41.Nd8+ Kd7 42.Nf7 Ke6 43.Nd8+

I originally intended 43.Nh,8 but feared I might have miscalculated and  my knight could get trapped. I therefore decided to return the knight to the white side of the board, knowing  I could always revisit the Nh8 idea if necessary.

43...Kd7 44.Nb7 Ke6 45.Nc5+ Kd6 46.Nd3 Ke6 47.Ke3 Bg2?!

This loses quickly. Best, according to the engines, is 47...Bd1 48.Nc5+ Kd6 49.Na6 Ba4 50.Kd4 Bb5 51.e5+ fxe5+ 52.fxe5+ Kd7 53.Nc5+ Ke7 54.Ke3 Bc4 55.Kf4 Ba2 56.Kg5 Bb1 57.Na6 Ke6 58.Kf4, when 58...Kd7 loses a pawn to 59.Nb8+. This is a long line, but there is nothing difficult about it for White.

48.f5+ gxf5 49.Nf4+ 1-0

Schools ... Outdoors ... Retail ... Pubs ... Chess?

ANYONE hoping for a quick return to over-the-board chess will have been disappointed, but probably not surprised, by Boris Johnson's speech in the Commons today.

The basic timetable is:

March 8 - schools reopen

March 29 - small outdoor gatherings allowed

April 12 - shops, gyms and beer gardens reopen

May 17 - pubs reopen with a rule-of-six

June 21 - all legal restrictions end, meaning nightclubs reopen and chess tournaments can be held

People hoping to play OTB chess before June 21 (and remember these dates could be put back) should probably look to Europe.

Many countries give official recognition to chess as either a sport or a cultural activity, which in practice should mean restrictions are lifted sooner.

One drawback with this scenario is that vaccinating the population is much more advanced here than on the Continent, so the lifting of restrictions in some European countries may be delayed.

And of course we have to await permission from the government to travel abroad again ...

Knight v Bishop (part 39)

White has just captured on c5 in Thomas Bergmann (1796) - Spanton (1890), Bad Wörishofen (Bavaria) U2000 2019. Who stands better, and by how much?

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White has the better piece for working with rival pawn-majorities, but Black has more space and the more-active king. The analysis engines Stockfish12 and Komodo11.01 reckon Black is very slightly better.

31...Kd5 32.Bb6 e4 33.Bc7

Not 33.fxe4+? Kxe4, when the black king is even more active.

33...Ne5

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34.Bxe5?

Swopping off into a pawn-ending may be the best plan, but this is the wrong way to do it. Better is 34.fxe4+ Kxe4 35.Bxe5 Kxe5, when 36.Ke3 equalises, according to Stockfish12 although Komodo11.01 reckons 36...g5 gives Black a winning advantage.

Note that 34.Ke3? loses to 34...Nc4+, but perhaps White can let the knight into d3 by playing 34.b3!? Then 34...Nd3+ 35.Ke3 Nc1 runs into 36.fxe4+ fxe4 37.c4+. The engines suggest 34...g5 or 34...f4, when Black may be slightly better.

34...Kxe5 35.fxe4?

White's game is difficult, but this makes matters worse as it improves the position of the black king.

35...Kxe4 36.Ke2 f4!?

This is strongly disliked by Stockfish12. Komodo11.01 at first is none too keen either but comes to make ...f4!? its top choice, at least for a while. Generally speaking, the engines prefer the less-committal 36...g5.

37.b4??

But this is definitely horrible. Sensible is 37.a4, keeping the white pawn-majority mobile.

37...b5 38.Kd2 g5 39.c4!?

Desperation, but White is lost anyway.

39...bxc4 40.Kc3 Kd5 41.a4 h5 42.b5 axb5 43.axb5 g4 44.hxg4 hxg4 45.b6 Kc6 46.b7 Kxb7 47.Kxc4 f3 48.gxf3 g3 0-1

New Stockfish

A POST at the English Chess Forum has alerted me to the fact that Stockfish13 is available to download for free from https://stockfishchess.org/download/

Knight v Bishop (part 38)

Black has just captured on g6 in Oliver Gill (2134) - Spanton (1954), Coulsdon (Surrey) Christmas 2018. Who stands better, and by how much?

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Black has doubled c pawns, no realistic hope of creating a queenside passer and a bishop that has no targets (apart from h3). White has an isolated pawn and difficulties creating a kingside passer. The analysis engines Stockfish12 and Komodo11.01 reckon the position is equal.

42.Ne3 Bd3!?

The engines do not like this, preferring 42...Bh5.

43.Kg3 Be2 44.Kh4

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44...Bf3?!

The engines reckon best is 44...f6, although after 45.exf6 they disagree as to how Black should recapture.

45.Kg5

Stockfish12 at first reckons this gives White a winning advantage, but fairly soon comes closer to Komodo11.01's assessment of a slight edge to White.

45...Be2

Not 45...f6+? 46.exf6 gxf6 47.Kg6 with a winning advantage for White, according to the engines.

46.h4 g6?

This weakens the kingside dark squares.

47.Kh6

The best way to exploit Black's mistake seems to be 47.Ng4, eg 47...Bf3 (47...Bxg4 48.Kxg4 is a winning pawn-ending for White) 48.Nf6 Be2 49.Ne8 Kd7 50.Ng7 Ke7 51.f5 Bd3 52.f6 Kd7 53.e6+ fxe6 54.Kh6 with an overwhelming position. One line give by the engines continues 54...e5 55.Nf5! Bxf5 56.f7 etc.

47...Bf3 48.Kg7 Be2 49.Kf8 Bb5?

Better is 49...Bh5, but White remains on top.

50.Ng4

This is probably good enough but even stronger is the engines' 50.c4, eg 50...Ba6 51.Ke8 followed by Kd8 etc. If 50...Ba4, then 51.Nd5, which is also the answer to to 50...Bc6.

50...Kf5 51.Nh6+ Kxf4 52.Nxf7 Kf5

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53.Kg7?

The correct plan seems to be 53.Ke7 (53.Nh8 may also be winning), supporting the advance of the e pawn.

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53...Be8?

The engines' 53...Be2 seems to draw. If then, as in the game, 54.Nh8, the continuation 54...Kxe5 55.Nxg6+ Kf5 leaves Black able to stop the h pawn.

54.Nh8 Kxe5?

And here it seems the engines' 54...Ba4!? gives drawing chances, eg 55.Nxg6 Bd1, stopping the h pawn. White can try 55.Kf7!? but 55...Bb3+ 56.Ke7 g5 57.hxg5 Kxg5 58.Kd7 Kf5 59.Kxc7 b5 60.Kc6 b4 seems to hold.

55.Nxg6+ Kf5 56.Ne7+ Kg4 57.Nd5 Kxh4 58.Nxc7 Bc6 59.Kf6 Kg4 60.Ke5 Kf3 61.Kd6 Be4 62.Nd5 Ke2 63.Nxb6 Kd3 64.Kxc5 Kc2 65.Na4 Kb3 66.Kb5 Bg6 67.Kxa5 Be8 68.Nb6 Kxb2 69.Kb4 Bh5 70.a4 Be2 71.a5 Kc2 72.c4 Kd3 73.a6 Kc4 74.a7 1-0

Knight v Bishop (part 37)

White has just captured on d4 in Olivia Smith (2033) - Spanton (1937), 63rd Hampstead (London) U2200 2018. Who stands better, and by how much?

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White has more space, but the bishop is bad and Black has much the better pawn-majority. Stockfish12 and Komodo11.01 reckon Black is winning.

32...g5 33.Ke3 Kg6 34.Bf1 Nc5 35.fxg5 hxg5 36.h4

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36...g4?

This throws away the win. 36...gxh4 and 36...Na4 win easily, as do most reasonable moves.

37.Kf4 Kh5!?

Probably not 37...Na4?! 38.h5+! Kxh5 39.Kxf5.

38.Kxf5 g3?!

The engines reckon Black draws with 38...Kxh4, but their best-play continuation is a long and quite-sharp one, viz 39.Kf6 Kg3 40.Be2! Kf4 41.Bxg4! Kxg4 42.Ke7 Nb7 (other knight moves also draw) 43.Kd7 a4 44.Kc6 Na5+ 45.Kxd6 Nxd4+ 46.Ke7 Nxb2 47.d6 a3 48.d7 a2 49.d8=Q a1=Q 50.Qxb6.

The text may also draw, but is less clear and, in my opinion, sets White fewer problems (although OS goes wrong immediately).

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39.Kf4?

White has to attack, eg 39.Kf6 Kxh4 40.Ke7 Kg4 41.Bg2 Kf4 42.Kxd6 Ke3 43.Bh1!? Kf2 44.Ke5 Kg1 45.Be4 (45.Bf3 Kf2) Nxe4 46.Kxe4 g2 47.d6 Kf1 48.d7 g1=Q 49.d8=Q, when Komodo11.01 reckons White has a slight edge, but Stockfish12 rates the position as dead-equal.

39...Kxh4

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40.Kf3?

This definitely loses. White again had to attack Black's queenside, starting with 40.Kf5, when Komodo11.01 reckons 40...a4 gives Black the upper hand, but Stockfish12 again rates the position as dead-equal.

40...Na4 41.Kg2

If 41.b3, then 41...Nc5 and 42...Nxb3.

The text is Komodo11.01's choice, but all moves lose.

41...Kg4 42.Be2+ Kf4 43.b3 Nc5 44.Bd1 Ke3 45.Kxg3 Kd2

White loses because the bishop has no targets and her king is out of play.

The game finished:

46.Bg4 Nxb3 47.Bf5 Kc3 48.Kf2 Kxc4 49.Ke1 Kxd5 50.Kd1 Nd4 51.Bd3 Kc5 52.Kc1 Nxb5 53.Kb2 d5 54.Be2 Nd4 55.Bd1 b5 56.Kc3 b4+ 57.Kb2 Nb5 58.Bc2 d4 59.Bd3 Nc3 60.Kb3 a4+ 61.Kb2 Kd5 62.Ka1 Ke5 63.Kb2 Kf4 64.Bg6 Ke3 65.Kc2 Ne4 66.Be8 d3+ 67.Kb2 Nc3 68.Bh5 d2 69.Kc2 d1=Q+ 70.Bxd1 Nxd1 71.Kxd1 Kd3 72.Kc1 Kc3 73.Kb1 Kb3 74.Ka1 Kc2 0-1

Knight v Bishop (part 36)

White has just captured on c1 in Spanton (1878) - Tobias Kolb (1740), Bamberg (Bavaria) U1900 2018. Who stands better, and by how much?

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The knight has a great square on d4, while the bishop is restricted by its own pawns. But Black has a protected passed pawn, and White a backward b pawn. The analysis engines Stockfish12 and Komodo11.01 reckon the position is dead-equal.

32...Kc7 33.Kb2 Kb6 34.Kc3 Kc5 35.Nf3 h6 36.g4 g6 37.h4 Bc6 38.Nd4 Bd7 39.Nc2 Bc6 40.Kd3 Bb7

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41.h5??

The engines' evaluations had not wavered from dead-equal, until this losing blunder.

41...Ba6+ 42.Ke3 gxh5 43.gxh5

The h5 pawn is very weak, and if White tries to protect it the d pawn advances.

43...Bf1 44.Nd4

No better is 44.Kf2 Bh3 45.Kg3 Bf5.

44...Bh3 45.f5!? Bxf5 46.b4+!? Kxb4 47.Nc6+ Kxa4 48.Nd8 Kb3 49.Nxf7 a4 50.Nxh6 Bh7 0-1

Knight v Bishop (part 35)

Black has just captured on c3 in Spanton (1977) - Christopher Archer-Lock (2053), Paignton 2012. Who stands better, and by how much?

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Stockfish12 reckons White has a slight edge, but Komodo11.01 calls the position equal.

39.Kf2

The engines want White to play 39.a4!? I rejected that because I wanted to leave a route for my king to enter Black's position via the queenside.

39...Kf8!?

The engines do not like this retreat, preferring, for example, 39...f6.

40.Ke3 Ke8!?

They still prefer ...f6.

41.Ke4 Kd7 42.Ng5 Bb2?

Better is 42...Ke8, but Black is clearly on the back foot, confirming that Black's king manoeuvre has probably been incorrect.

43.a4?!

Probably better is 43.Nxf7 Bxa3 44.Nh8 Bb4 45.Nxg6, as 45...a5 seems to be comfortably met by 46.Nf4, eg 46...a4 47.Kd3.

43...Ke8 44.e6 f6 45.Nf7?

White still seems to be winning after the engines' 45.Nh3, when the engines reckon best-play goes 45...Be5 46.Kf3 Kf8 47.g4 hxg4+ 48.Kg4, and now something like 48...Kg7 49.h5 gxh5+ 50.Kxh5 Bd4 51.Kg4 Kf8 52.Kf5 with very strong play.

45...f5+

From my original notes I see I missed that this allows Black to cover the h8 square.

46.Kf3 Bc3 47.Ng5 Kf8 48.Nh3 Kg7 49.Nf4

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49...Bd4?

Best, according to the engines, is 49...Be5. The point being that if, as in the game, 50.Nd3, Black can reply 50...Bd6, when the bishop simultaneously defends c5 and pressurises g3.

50.Nd3 Kf6 51.Kf4 a5

Black was in zugzwang, eg 51...Bg1 52.Ne5 Bd4 53.Nd7+ Kg7 54.Nb8 a5 55.Nc6 or 51...Kg7 52.Ne5 Bxe5+ 53.Kxe5 Kf8 54.d6 etc.

52.Kf3 Kg7 53.Nf4?

A mistake that allows Black to transpose into the line pointed out at Black's 49th move. The engines reckon 53.Nc1 is winning - Stockfish12 gives White an advantage of more than +7 while Komodo11.01 reckons almost +5. However, after 53...Bc3 (the only way to be able to defend a5 and c5) the engines go round in circles with lines such as 54.Nb3 Bb4 55.Ke3 Be1 56.Ke2 Bb4 57.Nc1 Bc3 58.Kf3 Bb4 59.Nd3 Kf6 60.Ke3 Ba3 61.Kf3 Bb4 62.Ke3 etc. At some point White has to break this cycle, eg 56.Nxc5!? Bxg3, when 57.Nb3 Bxh4 58.Nxa5 Bg3 59.c5 seems to win.

53...Kf6?

CA-L offered a draw.

54.Nh3?

Correct is 54.Nd3, transposing to the winning position after 52.Kf3.

54...Bc3 55.Ng5 Bb2?

Again Be5 holds, and if, as in the game, 56.Nf7, then 56...Bc7 stops the knight invading the queenside.

56.Nf7 Bc3 57.Nd8 Be1 58.Nc6 Bd2 59.Kf2 f4!?

If 59....Bc3 then 60.Ke2 Bb4 61.Nxb4 cxb4 62.Kd2 wins, eg 62...Ke5 63.Kd3 Kd6 64.Kd4 Kc7 (64...b3 65.c5+) 65.c5 Kd8 66.d6 exd6 67.c6!?, or 63...g5 64.hxg5+ Kxg5 65.d6 etc.

60.gxf4 Bxf4 61.Nxa5 Ke5 62.Nb7 Kd4 63.d6 1-0

Knight v Bishop (part 34)

Black has just captured on e4 in Spanton (1968) - Henrik Lobersli (1818), Fagernes (Norway) 2018. Who stands better, and by how much?  

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Black has the better minor-piece for working with rival pawn-majorities, but the e pawn is weak and will need supporting by ...f5, which further restricts the movement of the bishop. Stockfish12 and Komodo11.01 give White the upper hand.

30.Nd4

Not 30.Kxe4 Bc6+ and ...Bxg2.

30...f5 31.h4

The engines prefer 31.Ne2!? followed by Kd4.

31...Kf6 32.c4 Ke5 33.g3 g5 34.hxg5 hxg5 35.Ne2

The engines prefer 35.f4+!? but reckon Black is equal after 35...exf3!? (better than accepting  a protected passed pawn with 35...gxf4+, according to the engines) 36.Nxf3+ Kf6.

35...b5 36.c5?!

This seems over-ambitious. The engines prefer 36.cxb5 Bxb5 37.Nc3 or 36.Kd2!?

36...a5 37.Nc3

37.b4 axb4 38.axb4 Kd5 looks horrible for White although the engines come up with 39.Nc1!? Kc4 40.g4!, which seems to hold, eg 40...Kxb4 41.gxf5 Bxf5 42.c6 Ka3 43.Kd4 b4 44.c7 b3 45.Nxb3 Kxb3 46.Ke5 Bc8 47.Kxe4 Kc3 48.f4 g4 49.f5 g3 50.Kf3 etc.

37...b4?!

This allows equality. More promising is the engines' 37...Bc6, eg 38.b4 axb4 39.axb4 f4+ 40.gxf4+ gxf4+ 41.Kd2 Kd4, when White faces a tough defence.

38.axb4 axb4 39.Na2 f4+ 40.gxf4+ gxf4+ 41.Kd2 Kd4 42.c6!? Bxc6 43.Nxb4 bb5 44.Nc2+ Kc5 45.Kc3 Kd5 46.b4 Bf1 47.Nd4 Ba6 48.Nc2 Ke5 49.Nd4 Kf6 50.b5 Bb7 51.Kd2 Ke5

HL offered a draw.

52.Ne2 Bd5 53.b6 e3+!?

Black gives up a pawn, but the position remains dead-equal, according to the engines.

54.fxe3 fxe3+ 55.Kxe3 Kd6 56.Nc3 Bc6!?

There is nothing wrong with this objectively. But HL was short of time and there was no increment, so better from a practical view is 56...Bb7, when White cannot stop the black king from capturing the pawn and so ensuring a draw, eg 57.Kd4 Kc6 58.Nd5 Kb5.

57.Kd4 Bb7 58.Na4 Kc6 59.Kc4 Ba6+ 60.Kb4 Bb5 61.Ka5 Bc4

Not 61...Bxa4 62.Ka6.

62.Nc3 Kb7 63.Ne4 Bd5 64.Nc5+ Kb8 65.Kb5 Bf3 66.Nd7+ Kb7 67.Kc5 Bg2 68.Kd6

The black flag fell. A few moves earlier HL had claimed a draw, and an arbiter told us to play on to flag-fall, which came a few seconds later.

HL argued he should be awarded a draw as the position is drawn with anything but extremely stupid play by Black, which is indeed the case.

I argued that I was trying to make progress, as the game score showed, and it was not my fault if my opponent had run out of time.

There was a conflab among the congress's arbiters, and after several minutes the verdict came back as a "borderline" win for me.

Knight v Bishop (part 33)

White has just captured on d1 in Yves Duhayon (2210) - Spanton (1984), Gibraltar 2012. Who stands better, and by how much?

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White has an extra pawn-island, but has more space and the better minor piece for dealing with mobile pawn-majorities. Stockfish12 gives White the upper hand, but Komodo11.01 reckons White at best has a slight edge.

23...f5!?

Keeping the e pawn backward, at least temporarily, but making the f5 pawn a potential target for the white bishop.

24.Bf3

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24...b6!?

It was difficult choosing between this and 24...c6. The engines agree with my choice but reckon the difference between the two moves is only the equivalent of about a quarter of a pawn.

25.Ke2 Kf7 26.Kd3 Ke6?!

The engines much prefer gaining space with 26...c5.

27.Kd4 Kd6 28.c5+ bxc5+ 29.bxc5+ Ke6 30.Kc4 c6

I see from my original notes that Houdini1.5a reckoned Black equalises with 30...Kd7. It continued 31.Kb4 Nc6+ 32.Bxc6?! Kxc6 33.Kc4 g6=. But my modern engines reckon the further moves 34.a4 a5 35.h4 h5 36.Kd4 Kd7 37.Ke5 Kc6 38.Kf6 etc give White good winning chances - both sides will queen, but with White a pawn up.

However, as I had seen over the board, White has what seems to be a major improvement in 32.Ka4, playing for zugzwang, eg 32...g6 33.h4 h6 34.Bh1 Nb8 35.Ka5 Ke7 36.Bd5 Kf6 37.Bc4 Nd7 38.Bxa6 Nxc5 39.Kb5, after which the a pawn is powerful and the c pawn weak.

31.Kb4 Nd5+!?

The engines prefer 31...Kd7 32.Ka5 Kc7, but after 33.Ka6 White has a large advantage. Actually, after being shown the text, Komodo11.01, comes to prefer it. The practical advantage of the text is that it gives Black counterplay.

32.Ka5 Nxe3 33.Kxa6 Nd5 34.Kb7 Nxf4 35.a4!?

Stockfish12 gives 35.Bxc6, but Komodo11.01 prefers the text (after being shown it).

35...Nd3 36.Kb6 Ne5 37.Bd1?!

37.Bxc6!? Nxc6 38.Kxc6 f4 39.Kb7 etc is winning, according to Komodo11.01, but only slight better for White, according to Stockfish12.

Best seems to be 37.Bh1 (also strong is 37.Bg2), keeping pressure on c6, eg 37...f4 38.Kc7 f3 39.a5 f2 40.Bg2 etc.

37...f4?

Black has good drawing chances after 37...Kd7 (this would not work after 37.Bh1 as then 37...Kd7 is met by 38.Kb7, followed by advancing the a pawn) since White has less pressure on c6. So 38.Kb7 runs into 38...Nd3.

38.Bb3+?

Winning is 38.Kc7 followed by pushing the a pawn.

38...Kd7

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39.a5?

White draws with 39.Bc2, according to the engines. Possibly 39.Kb7 also holds, but is not clear.

39...f3 40.Bd1 Nc4+!? 41.Ka6 Kc7

The white king is trapped on the a file - the point of my 40th move.

42.Bxf3

White has restored equality in pawns, but only temporarily, and anyway Black is a pawn up on the kingside in what has become a battle between knight and bishop without the kings interfering.

42...Ne5 43.Be4 g6 44.Ka7 Nd7 45.Bc2 Nxc5 46.h4 Ne6 47.a6 c5 48.Ka8 Nf4 49.Be4 c4 50.h5 gxh5 0-1

Knight v Bishop (part 32)

Black has just captured on e8 in Francisco Lopez Colon (2251) - Spanton (2026), Benidorm (Spain) U2301 2009. Who stands better, and by how much?

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The white king is much better than its black counterpart as it can centralise more quickly.. White also has the better pawn-structure and the more-mobile minor piece. These factors add up to a winning advantage, according to the analysis engines Stockfish12 and Komodo11.01.

24.Bd3 Nf6 25.Kc3 Kc8 26.Kd4 Kd7 27.Ke5 Nd5 28.a3 h6 29.Kf5 Nc3 30.Kg6 Ke6 31.Kxh6 Ke6 32.Be4 Nb5!?

The engines prefer 32...Nd1, but with a winning advantage for White.

33.a4 Nd6 34.Bxc6 Nf5+ 35.Kh5 Ng7+ 36.Kg4 Ne6 37.Bd5 Nd4 38.h4 1-0

Knight v Bishop (part 31)

White has just captured on c5 in Siegfried Halwachs (1910) - Spanton (2034), Liechtenstein 2009. Who stands better, and by how much?

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White has the upper hand, according to Stockfish12; a slight edge, according to Komodo11.01

36...Kd7 37.Kd5

The engines give best play as 37.Kb6 Kc8 38.b5!? axb5 39.Bc3 Nf7, when Stockfish12 reckons 40.Bb4 gives White a winning position, but Komodo11.01 replies 40...e4, with just a slight edge for White. The engines then agree that best play continues 41.Kxb5 Ne5 42.Bf8 g6 43.Bg7 Nd7 44.Kc4 Kd8, when Komodo11.01's evaluation continues at a slight edge for White, while Stockfish12 reckons White, although not winning, has the upper hand.

37...Nc6 38.f4!? Ne7+ 39.Ke4 exf4 40.exf4 Ke6 41.g4

SH offered a draw. The engines reckon the position is dead-equal.

41...f5+ 42.Kf3 g6 43.gxh5 gxh5

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44.Kg3?

The position is still equal after 44.Ke3 or 44.Ke2, according to the engines.

44...Ng6 45.Bd4 Kd5

This is also the answer to 45.Kf3. White's problem is defending f4 while at the same time preventing the black king penetrating the queenside.

46.Bc5 b5 47.Kf3

Or 47.Be3 Kc4 etc.

47...Kc4 48.Bd6 Kb3 49.Ke3 Kxa3 50.Kd4 Nxf4!? 51.Ke5

If 51.Bxf4 then 51...Kxb4 is a fairly easy win for Black. The engines give best play as something like 52.Bd2+ Kb3 53.Kc5 Kc2 54.Bg5 Kc3 55.Kb6 (55.Bf6+ Kd3) b4 56.Kxa6 b3 57.Kb6 Kc2 58.Bf6 f4 etc.

51...Nxh3 52.Kxf5 Nxf2 53.Be7 Nd3 54.Kg5 Nxb4 55.Kxh5 Kb3 56.Kg4 a5 57.Kf3 Nd5 58.Bf8 a4 59.Ke4 Kc4 0-1

Knight v Bishop (part 30)

White has just captured on f4 in Spanton (2017) - Leif Kverndal (1914), Gausdal (Norway) Elo 2008. Who stands better, and by how much?

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The bishop is restricted by the black central pawns, and Black has a backward e pawn, although that is not really a weakness White can get at, any more than Black can get at White's isolated queen's pawn. Black has more space on the kingside, but White has chances of creating a passed pawn there. The analysis engines Stockfish12 and Komodo11.01 reckon the position is equal, but to me it looks much easier for White to play.

35...Bc6?

Activating the bishop, but it runs into a tactical refutation. Good is 35...Kf6.

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36.Kf1?

Missing that 36.Nd3 sets up a triple fork on e5.

36...Kf6 37.Nd3 Kf5 38.f3!?

Keeping the black king out of e4, but giving up hope of creating a kingside passer. 38.Nc5 also keeps the black king out of e4, but allows 38...e5.

38...gxf3 39.gxf3 Be8 40.Kf2 Bh5 41.Ke3 Be8

Black seems to have no way to improve his position. The engines still rate the position as equal, but a draw is all Black can expect while White can probe for more.

42.Ne5 Kg5 43.f4+ Kf5 44.h3 Kf6!?

Evaluate this move.

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In my original notes I gave ...Kf6 two question marks, thinking the move loses the game for Black. But it probably does not!

I was expecting 44...Bh5, to which I planned to play 45.Nc6, but 45...Be8! holds for Black, eg 46.Nxa7 Bd7 47.Kf3 Kf6, when apparently neither side can make progress. If 48.Kg4!? the engines give 48...e5+ 49.Kxh4 exf4 50.Nxb5! Bxb5 51.Kg4 Bd7+ 52.Kxf4 Bxh3 as being equal, eg 53.b5 Bf1 54.a4 Ke6 55.Ke3 Bc4 56.Kd2! Kd6 57.Kc3 Kc7 58.Kb4 Kb6 59.a5+ Kb7 60.Kc5 with again neither side able to make progress. 

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45.Nf3

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45...Kf5?

Black has good drawing chances after 45...Bg6 46.Nxh4 Bf5 47.Nf3 (47.Nxf5 exf5=) Bxh3 48.Ne5 Bf5 49.Nc6 Bg6 50.Nxa7 Be8 51.Nc8 Bd7. White is a pawn up but Black seems able to hold (Stockfish12 reckons the position is dead-equal, but Komodo11.01's evaluation of a slight edge for White is surely more accurate).

46.Nxh4+ Kf6 47.Nf3 Kf5 48.Ne5 Kf6 49.Nd3 Kf5 50.Nc5 Kf6 51.Nb7 a6?

Throwing away another pawn.

The game finished:

52.Nc5 Bh5 53.Nxa6 Bd1 54.Nc7 Ba4 55.h4 Kf5 56.h5 Kf6 57.h6 Kg6 58.Nxe6 Kxh6 59.Nc7 Kg6 60.Nxd5 Bb3 61.Nc3 Bc4 62.Ke4 Kf6 63.d5 Ke7 64.Ke5 1-0

Knight v Bishop (part 29)

White has just captured on d2 in Matias Ruiz Viñals (2038) - Spanton (2005), Linares (Spain) Open 2003. Who stands better, and by how much?

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Rival pawn-majorities usually favour the bishop, but here it is not easy for White to create a passer from his majority. Black has an isolated e pawn. Stockfish12 and Komodo11.01 give a tiny edge to White.

23...Nc6 24.Bf4 e5!?

This makes the pawn a potential target for the bishop, but claims an equal share of space in the centre and supports the knight landing on d4.

25.Be3 Ke6 26.f4!?

This dissolves Black's isolated pawn while granting White a passed but isolated e pawn, and also takes away half of the support for a knight on d4.

26...exf4

My original notes call 26...Nd4!? "safer," but I am no longer so sure about this. My modern engines prefer the text.

27.Bxf4 a6 28.a3 b5 29.Be3 c4!?

29...Ke5 30.Bxc5 Kxe4 is dead-equal, according to the engines.

30.Bb6 g6 31.Ke3 h6 32.Bc7 Kd7 33.Bf4

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33...g5!?

I found it tough choosing between this and 33...h5, but decided the key factor was keeping the white king out of the kingside. The engines agree with my choice.

34.Bg3 Ke6 35.Be1 Ne5 36.h3 Nd3

A great outpost for the knight, but the position is still equal, according to the engines.

37.Bc3 Nf4 38.Kf3 Nd3 39.Bd4 Ne1+ 40.Kf2 Nd3+ 41.Ke3 Nf4 42.Kf3 Nd3 43.g3

43.Kg4!? leads to sharp play but seems to give equal chances, eg 43...Nf4 44.Bg7 Nd3 45.Kh5 Nf2 46.Bxh6 Nxe4 47.Bxg5 Nxg5 48.Kxg5 a5 49.Kf4 b4 50.Ke4 (50.axb4? c3!) c3 51.Kd3 (51.bxc3?? bxa3) cxb2 52.Kc2 bxa3=. But the engines point out many plausible alternatives in this line, especially early on.

43...Ne5+

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44.Ke3

Not 44.Bxe5? Kxe5, eg 45.Ke3 a5, after which the white king will eventually be distracted to the queenside, allowing Black to clean up on the kingside.

44...h5 45.Bc3 Nc6 46.Bg7 Ne5!?

This allows the white king to penetrate the queenside, and so leads to sharp play.

47.Kd4 Nf3+

47...Nd3 is met by 48.b3, also with equal play, according to the engines.

48.Kc5 Nd2

It was difficult choosing between this and 48...Ng1. Stockfish12 reckons both moves leave the position dead-equal, but Komodo11.01 marginally prefers 48...Ng1.

49.Kd4

A change of heart, but maintaining equality. Also equal is 49.Kb6 Nxe4 50.g4 hxg4 51.hxg4 Kd5 52.Kxa6 Kc5.

49...Nf1 50.g4 hxg4 51.hxg4 Nh2 52.Bh6 Kf6 53.e5+ Ke6

Also equal is 53...Kg6!?, eg 54.e6 Nxg4 55.Bxg5!? Kxg5 56.e7 Nf6 57.Kc5 etc.

54.Ke4?!

Drawing is 54.Kc5 Nxg4 55.Bxg5 Nxe5 56.Kb6 etc, and even 54.Bxg5!? Nf3+ 55.Kc5 Nxg5 56.Kb6 etc.

54...Nxg4 55.Bxg5 Nxe5

Stockfish12 reckons the position remains dead-equal, but Komodo11.01's assessment of a very small edge for Black, albeit one of less than a fifth of a pawn, must surely be closer to the truth, at least from a practical view.

56.Bd2!?

Komodo11.01 strongly dislikes this, preferring 56.a4 or 56.Be3, but Stockfish12 reckons the position is still equal.

56...Nd3 57.Bc3 Kd6 58.Kd4 Nc1 59.Ke3?!

Giving ground seems strange and is not liked by Komodo11.01, but Stockfish12 is OK with it.

59...Kd5 60.Kd2 Nb3+ 61.Kc2!?

This is Komodo11.01's choice. Stockfish12 likes the text and 61.Ke3 equally.

61...Ke4 62.Bf6 a5 63.Bd8 Nd4+ 64.Kc3 Nc6

By now the engines agree there is no way for Black to make progress.

65.Bc7

65.Bxa5!? Nxa5 66.Kb4 etc is one draw.

65...Kd5 66.Bg3

66.Bxa5!?=

66...b4+ 67.axb4 axb4+ 68.Kd2 Nd4 69.Bf4 Nf3+

The game should still be drawn, but now White has to find an only-move.

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70.Kc2

Not 70.Ke3 c3 71.bxc3 (71.b3 Nd4) b3 72.Kd3 Ne1+ 73.Kd2 b2.

But 70.Ke2!, eg 70...Nd4+ 71.Kd2 Ke4 72.Bd6.

70...Ne1+ 71.Kb1

Both 71.Kd2? and 71.Kc1? make it easy for Black after 71...Nd3(+). Even after the text, Black has two winning moves.

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71...Kd4?

But this is not one of them. 71...Nd3 and 71...b3 win, eg 71...Nd3 72.Bg5 b3!(only-move, although the engines mistakenly give 72...Ke4 as also winning) 73.Bd2 Ke4 74.Bg5 Kf3 75.Bh6 Ke2 76.Bg5 Kd1 77.Bf6 Nc5 78.Bd4 Ne4 79.Be5 Nd2+ 80.Ka1 Kc2 81.Bc3 Nb1 82.Ba5 c3 83.bxc3 b2+ 84.Ka2 Nxc3+ 85.Bxc3 b1=Q+ (but not 85...Kxc3?? 68.Kb1=) etc. Main analysis: Syzygy tablebase.

After the text, Komodo11.01 reckons Black is winning, but Syzygy shows White has two drawing moves.

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72.Bh6?

Both 72.b3!? and 72.Bd2 draw, eg 72.Bd2 Nd3 73.b3! c3 74.Bg5 Nc5 75.Kc2, or 73...cxb3 74.Bg5 Kc4 (74...b2 75.Bf6+ Kc4 76.Bxb2=) 75.Bd2 - in neither line can Black make progress.

72...b3

Also winning is 72...Kd3.

73.Bg7+ Kd3 74.Bc3 Nc2 75.Bg7 Nb4 76.Bf6 Na2 77.Bg7 Kd2 78.Bf6 Kd1 79.Bg7 Nc1 80.Bf6 Nd3 81.Bg7 Ne1 82.Bf6 Nf3 83.Bg7

Or 83.Bc3 Nd2+ 84.Bxd2 Kxd2 85.Ka1 c3 86.bxc3 Kc2 etc. In this line White can try 84.Ka1 Kc1 85.Bd4 Nf3 86.Be5!? Ne1 87.Bf4+ Kc2 88.Bh6 Nd3 89.Bg7, but then comes 89...Nxb2! 90.Bxb2 c3 91.Bxc3 Kxc3 92.Kb1 b2 etc.

83...Nd2+ 84.Ka1 Kc2 85.Bf6 Ne4 86.Be5 Nc5 87.Bf6 Na4 88.Bg7 Nc3 89.Bf6 Nxb2 90.Bg7 Na4 91.Bxc3 Kxc3 0-1

Knight v Bishop (part 28)

Black has just captured on d8 in Spanton (2081) - R Myhrvold (2253), Bergen (Norway) 2000. Who stands better, and by how much?

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Black has much the better pawn-structure, and the better minor piece for working with rival pawn-majorities (not that the white majority is likely to produce a passed pawn anyway). Stockfish12 gives Black the upper hand, but Komodo11.01 reckons Black only has a slight edge.

23.Kc2 Kc7

Not 23...c3? 24.b3 and 25.Kxc3.

24.Kc3 b5?!

Probably better is 24...Kd6

25.Kb4?

Much better is 25.Nd4 Bd7 26.a4.

25...Kb6 26.Nd4?!

The one good thing about the white position is that the knight has a central outpost, but that is of little consolation as the black queenside majority is fast-moving. However, better here seems to be 26.a4 a5+ 27.Kc3 b4+ 28.Kd4 Bd7 29.Nd2 c3! 30.Nc4+ Ka6 31.bxc3 bxc3 32.Kxc3 Bxa4, although Black is for choice.

26...a5+ 27.Kc3 b4+ 28.Kd2 Bd7 29.Kc2 Kc5 30.Kd2 Kd5 31.Nc2 Ba4 32.Nd4

White has no real possibility of counterplay, and must wait for Black to attack.

32...g6 33.Nf3 Ke4 34.Nd4 Bd7 35.Nc2 Kf5 36.Nd4+ Kg4 37.Nf3 Kh3

I see from my original notes "I was close to resigning here." The engines agree resignation is justified - Black is +4.46, according to Komodo11.01; +7.5, according to Stockfish12.

38.e4 Be6?!

This maintains Black's winning advantage, but I doubt if RM would have played it if he had taken my next move seriously.

39.e5!?

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39...h6?

This turns a win into a loss.

Better is 39...Kg4 40.exf6 Kf5 with approximate equality (also equal, according to the engines, is 40.Nd4 c3+ 41.bxc3 bxc3+ 42.Kxc3 Bxa2).

But winning, according to the engines, is 39...fxe5!! 40.Ng5+ Kxh2 41.Nxe6 h5, one plausible line being 42.Nf8 g5 43.Ng6 Kxg3 44.Nxe5 h4 45.Nxc4 (45.Nf3 g4)  h3 etc.

40.exf6 g5 41.Ne5!?

This probably wins but the engines' 41.e4 is more solid.

41...g4

More challenging seems to be 41...Kxh2 42.f7 Bxf7 43.Nxf7 Kxg3 but 44.Nxh6 Kf4 45.e3+ Ke4 46.a4!? appears good enough for White.

42.f7 Bxf7 43.Nxf7 h5 44.e4 Kxh2 45.e5 Kxg3

Or 45...h4 46.Nh6 Kxg3 47.e6 h3 48.e7 h2 49.e8=Q h1=Q 50.Qe5+, after which Black cannot prevent queens coming off, leaving White with an easy win.

46.e6 h4 47.e7 h3 48.e8=Q Kg2 49.Qe4+ 1-0

Knight v Bishop (part 27)

Black has just captured on e6 in Spanton (165) - Oliver Rosten (195), International Students House (London) 1996. Who stands better, and by how much?

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Rival pawn-majorities favour the bishop, but this is offset by White having two isolated pawns. Stockfish12 and Komodo11.01 reckon the position is dead-equal.

33.c4!?

Ideally, White should put as many pawns on light squares as possible so the pawns control the light squares and the bishop can control the dark squares. But it is important such pawns are not vulnerable to a quick strike by the knight, or by the black king. And naturally at some point the kingside white pawns must cross dark squares so the white pawn-majority can advance.

33...Ne8 34.Ke3 Kd6 35.f4 g6 36.Bb2 Kc6 37.a4 Nd6 38.Kd3 a6

The engines prefer 38...f5!?, when White faces a tricky choice between 39.e5 (preferred by Komodo11.01), which creates a protected passed pawn but leaves a lot of white pawns obstructing the bishop, and 39.exf5 (preferred by Stockfish12), which gives the bishop more freedom but makes it difficult for White to activate his majority after 39...gxf5 and ...h5.

39.Be5 Nb7 40.g4 b5 41.axb5+ axb5 42.cxb5+ Kxb5

White's queenside weaknesses have gone but Black has the only passed pawn. The bishop is still better than the knight as it can support its own pawn-majority while at the same time help to slow the black passer. The engines reckon the position is equal.

43.f5!?

This seems the quickest way to create a white passer.

43...c4+?!

The engines do not like this, preferring 43...Kc6 or 43...gxf5, the former effectively accepting that it is too early to push the c pawn.

44.Kd4

This centralisation leaves the white king well-placed.

44...Kb4?!

The engines prefer 44...Nc5 but after, say, 45.Kd5 gxf5 46.gxf5 Na4, reckon White is winning with both 47.Kd6 and 47.Bf4.

45.fxg6?!

This seems to throw away much of White's advantage. The engines reckon White is winning after, for example, 45.Kd5 gxf5 46.gxf5 c3 47.Bf4.

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45...fxg6?

It seems 45...hxg6!? may gives good drawing chances. After 46.h4 Nd8 47.Ke3 Ne6 48.h5 Stockfish12 rates the position as at best just slightly better for White, although Komodo11.01 reckons White is winning. After the text White's passed e pawn is very strong.

46.Bf4 c3 47.e5 Nc5 48.Kd5 c2

OR offered a draw.

No better than the text is 48...Nd3 49.Bg5 c2 50.e6 c1=Q 51.Bxc1 Nxc1 52.e7 etc.

49.e6 Na6 50.Kc6 Kb3 51.e7 Nb4+ 52.Kd7 Nb5 53.Bc1 Nf6+ 54.Kd8 1-0

Knight v Bishop (part 26)

Black has just captured on e6 in Spanton (163) - Joseph Soesan (162), Guernsey 1994. Who stands better, and by how much?

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White is winning, according to Stockfish12; has the upper hand (+.96), according to Komodo11.01.

41.Ke3 f5

Komodo11.01 likes this but Stockfish12 prefers 41...Bd5. Note that meeting the latter with 42.Nxd5?? turns a win into a losing pawn-ending.

42.Kd4 Bg2

One of Black's problems is that the bishop has no targets, unlike the knight, and can do little to protect the black weaknesses.

43.Na4 Bf1 44.Nb6 Be2 45.Nc8 Bf1 46.Nd6 b6

Little better is 46...b5 47.Ne8 and 48.Nc7(+).

47.Ne8 bxc5+ 48.Kxc5 g6 49.a4 Kd7 50.Nd6 Be2 51.Nf7 Bd1 52.a5 1-0

Knight v Bishop (part 25)

Black has just captured on c5 in Spanton (156) - A Cohen (166), Highbury (London) Rapid 1991. Who stands better, and by how much?

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Black is winning, according to the analysis engines Stockfish12 and Komodo11.01.

34.Ne3

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34...Bd4?!

Black has many good moves, but this is probably not one of them. Best, according to the engines, is 34...Bxe3 35.fxe3 Kd6 36.Kc2 Kc5 37.Kc3 f6 38.Kb3 f5 39.exf5 gxf5 40.h4 f4 41.exf4 exf4 42.Kc3 h5, when White is in zugzwang. That is a long line but fairly straightforward.

35.f4

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35...Bxe3?

Capturing on e3 is no longer so good. The engines like 35...Bc5, with the better game for Black, but not necessarily winning.

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36.fxe3?

Losing, whereas 36.Kxe3 is dead-equal, according to the engines.

36...Kd6

After 36.Kxe3, playing 36...Kd6 is nothing for Black thanks to 37.fxe5+ Kxe5 38.f4+.

37.Kc3

No better is 37.fxe5+ Kxe5, when Black has all the reserve tempi he could possibly need.

37...Kc5 38.h4

Or 38.fxe5 g5 etc.

h6 39.Kb3 0-1

I resigned without waiting to see 39...exf4 40.exf4 Kd4 etc.

Knight v Bishop (part 24)

White has just captured on f3 in Spanton (147) - Justin Baptie (164), British Chess Championships Major (Eastbourne) 1990. Who stands better, and by how much?

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This is a typical minor-piece ending arising from the Exchange Variation of the Spanish. White has the better pawn-majority, but the white queenside pawns are fixed on dark squares and so are potentially vulnerable to the black bishop. Stockfish12 reckons White has a slight edge, while Komodo11.01 gives White the upper hand.

38...b4?

The engines give 38...a4, the point being to prevent White playing a4. A plausible continuation is 39.Ke4 Ke6 40.h5 gxh5 41.gxh5 b4 42.Nh4 bxa3 43.bxa3 Ba5 with good drawing chances.

39.Ke4?!

This may be good enough to win, but much clearer is 39.a4, after which the c4 pawn will fall and Black will have great difficulty getting at White's queenside pawns.

39...Bc7?

Again ...a4 gave the best drawing chances, and if 40.Kd5 then 40...Bc7, eg 41.Nh3 h5 42.gxh5 gxh5 43.Kxc4 bxc3 44.bxc3 Bd6, which the engines reckon is dead-equal. A better try for White is probably 40.f5, but the engines reckon White is, at best, only slightly better.

40.a4

Now the win is simple.

40...Ke6 41.h5 gxh5 42.gxh5 b3 43.Nd1 Bd8 44.Ne3 Bf6 45.Nxc4 Kf7 46.Kd5 1-0

Knight v Bishop (part 23)

White has just captured on d1 in Simon Spivack (188) - Spanton (151), Middlesex League Division 3 1990. Who stands better, and by how much? 

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Black's queenside pawns are shattered, but the king is more centralised than White's. Stockfish12 gives White a slight edge, while Komodo11.01 reckons the position is dead-equal.

32...Kd4 33.Kd2 Bf7 34.Ne2+ Kc5!?

Keeping the king in the centre with 34...Ke5 may be slightly better.

35.Ng3 Bd5?!

The engines prefer 35...Bg6 or 35...Kd4!? One point about the latter is that 36.Nf5+ Ke5 37.Nxg7?! runs into 37...f5 38.Kc3 Kf6, winning the knight. Even this is not entirely clear as 39.Kb4!? Kxg7 40.c3 Kf6 41.Ka5 confuses the issue, but is probably winning for Black.

36.f3

The engines slightly prefer 36.Nh5!? Bxg2 37.Nxg7.

36...g6 37.Ke3 Kd6 38.Nf1 Ke5 39.g3 f5?
I offered a draw, but the text gives Black strong winning chances. The problem with the move is that after ...

40.f4+ Kd6 41.Kd4

... Black cannot save the c4 pawn. So much better than my 39th move is 39...g5 or 39...h5. For example, after the latter, 40.f4+ can be met by 40...Kf5, when Black's play against the white kingside stops White going after the c4 pawn.

41...Be4

Or 41...c5+ 42.Kc3 and 43.Ne3.

42.Ne3 h6 43.Nxc4+ Ke6 44.c3 g5 45.Kc5 gxf4 46.gxf4

I sealed (remember those days?) ...

46...Kd7

... but resigned without resuming.

Knight v Bishop (part 22)

Black has just captured on e7 in Spanton (151) - Julien Shepley (163), Barbican (London) Rapid 1989. Who stands better, and by how much?

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Rival pawn-majorities favour the bishop, but that is the only major factor to Black's advantage. The bishop has no real targets (h2 is easily defended, and hard to get at), while the fixed nature of the queenside pawns will make the black ones vulnerable if the knight can get at them. In addition White has a protected passed pawn, meaning an exchange of minor pieces will almost always be hopeless for Black. Stockfish12 reckons White is winning, but Komodo11.01 gives White only a slight edge.

32.Kf3!?

Komodo11.01 is happy with this but Stockfish12 strongly dislikes it, preferring 32.g4, which gets a white pawn off the same coloured square as the bishop as well as gaining kingside space. Certainly White should not fear 32...f5?! as 33.gxf5 gxf5 34.Nf4 is good for White.

After the text, Stockfish12 reckons White only has a slight edge, but Komodo11.01 now reckons White has the upper hand.

32...f5 33.Kf4 Kf6 34.h3

The engines prefer 34.h4!? One point is that fixing White's kingside pawns with 34...h5? runs into 35.d6! Ke6 36.Kg5 etc.

34...g5+

The engines reckon 34...Be5+!? draws, eg 35.Kf3 Bd6 36.g4 h6 37.gxf5 Kxf5 38.Nf2 Bf8 39.Ne4 h5, when it is hard to see how White makes progress.

35.Kf3 h5!?

The engines strongly dislike this, preferring 35...Ke7 or 35...Bg1, but is far from clear they are correct.

36.Nf2

Komodo11.01 gives 36.h4 g4+ 37.Kf4, claiming White is winning. But after 37...Bc3 38.Ke3 (Black threatened 38...Bd2#) Bd4+ 39.Ke2 Be5 White has nothing better than 40.Nxe5 Kxe5 41.Ke3, when Stockfish12 is right to evaluate 41...f4+! 42.gxf4 Kf5 as a draw. Komodo11.01 still claims White is winning, but the mutual protected passed pawns mean neither side can make progress.

36...Be5 37.Nd3 Bd6 38.Kf2 h4?!

Black creates a passed pawn, but after ...

39.gxh4 gxh4

... the white king can advance, and h4 becomes a fixed target.

40.Kf3 Kg5 41.Nf2 Kg6 42.Nd3 Kf6

The engines reckon the text and 42...Kg5 are equally strong, with White having a slight edge in either case. The latter move can be met by 43.Kf3 Kf6 44.Nf4 with play similar to the game.

43.Nf4 Kg5 44.Ne6+ Kg6?

Correct is 44...Kf6, and if, as in the game, 45.Nd8 Bc7 46.Nb7 Bb6 then 47.d6!? does not win as Black simply replies 47...Ke6.

45.Nd8 Bc7 46.Nb7 Bb6 47.d6! Kf7 48.d7 Ke7 49.d8=Q+ Bxd8 50.Nxd8 Kxd8

Black is temporarily a pawn up, but is lost.

The game finished:

51.Kf4 a4!? 

Or 51...Kd7 52.Kxf5 Kd6 53.Kf6 Kd7 54.Ke5 etc.

52.Kxf5 axb3 53.axb3 Kd7 54.Kg4 Ke6 55.Kxh4 Ke5 56.Kg5 Kd4 57.h4 Kc3 58.h5 Kxb3 59.h6 Kxc4 60.h7 b3 61.h8=Q Kb4 62.Kf4 c4 63.Ke3 c3 64.Qd4+ Ka3 65.Qxc3 Ka2 66.Qa5+ Kb2 67.Kd2 Kb1 68.Qc3 b2 69.Qc2+ Ka1 70.Qa4+ Kb1 71.Kc3 Kc1 72.Qc2#

Knight v Bishop (part 21)

White has just captured on a6 in Spanton (151) - S Gallagher (132), Highbury (London) Rapid 1989. Who stands better, and by how much?

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Black has three isolated pawns, two of them doubled. But it is easy for Black to undouble his c pawns and, in the process, give White an isolated e pawn. Black also has the better minor piece for dealing with unbalanced pawn-structures, but White should find it easier to create a passed pawn. The analysis engines Stockfish12 and Komodo11.01 reckon the position is dead-equal.

38...Kb6 39.Nb4 Bd4+ 40.Ke2 dxe4 41.fxe4 Be5 42.h3 Kc5 43.a3 Bc3

Not 43...Bb2?? 44.Nd3+.

44.Nc2 Be5 45.Kd3 Kb6 46.Ne3 Bb2 47.a4 Be5 48.Nd5+ Ka5 49.axb5 Kxb5 50.Ke3 Bg3 51.Ke3 Be5 52.g4 h4!?

Both the text and 52...hxg4+ leave the position dead-equal, according to the engines.

53.g5 Bg3 54.Ke3 Be5 55.Kd3 Bg3 56.Nc7+ Kc6 57.Nd5 Be5!?

As the move 52...h4!? suggested, SG seems to be playing for a win, or at least to avoid a simple draw.

58.Kc4 Bg3 59.b4 Be1?

The engines reckon Black needed to keep the bishop protecting d6.

60.b5+ Kb7 61.Nf6 Bd2 62.Nh7?

Winning is 62.Ne8 Bxg5 63.Nxd6+ and 64.Nxf7.

62...Bf4 63.Kd5 Be5 64.Nf6 Bf4?

Drawing is 64...Bxf6 65.gxf6 g5 66.Kxd6 g4 67.e5 gxh3 68.e6 fxe6 69.f7 h2 70.f8=Q h1=Q 71.Qe7+.

My scoresheet ends after the text, but I did go on to win. The engines reckon best play is 65.Ne8 Bxg5 66.Nxd6+ and 67.Nxf7, when White is the equivalent of more than eight pawns up.

Knight v Bishop (part 20)

White has just captured on c2 in Spanton (151) - Maurice Staples (198), London League Division 3 1989. Who stands better, and by how much? 

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Rival pawn-majorities usually favour the side with the bishop, but Stockfish12 and Komodo11.01 reckon the position is equal. I think this is because Black has more space on the queenside, where the white pawns are somewhat restricted, and has the more-active king.

32...b5 33.a3 a5 34.Kd2 Ke6 35.Ke2 Kf6 36.Kf3 Ke6 37.Kg3!?

Hoping to penetrate on the kingside, but decentralising a slow-moving piece such as the king is often double-edged. I presume I must have overestimated my position, and was pushing for a win, when playing for a draw was more realistic. Having said that, the engines still rate the position as equal.

37...b4 38.axb4 axb4 39.Bc5?

White preserves the draw with 39.cxb4 Nxb4 40.Bd2, according to the engines.

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39...bxc3?!

Black is winning after 39...b3 40.Be3 d4! 41.cxd4 Nb4 42.Bd2 Nd3 43.Bc3 Nc1 44.Kf3 Na2, threatening ...Nxc3.

40.bxc3 d4! 41.cxd4 c3

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42.Kf3

The engines' 42.Kh4! seems to draw, eg 42...c2 43.Ba3 Nxd4 44.Kg5 Kf7 45.f5 gxf5 46.gxf5 Nb3 47.Kh6 Kg8 48.f6 etc.

42...c2 43.Ba3 Nxd4+ 44.Ke4 Ne2 45.f5+ gxf5+ 46.gxf5+ Kf7 47.Ke5 c1=Q 48.Bxc1 Nxc1

White cannot in time threaten the h7 pawn while advancing the f pawn.

The game finished:
49.f6 Nb3 50.Kf5 Nc5 51.Kg5 Ne4+ 52.Kh6 Nxf6 53.h4 Kg8 54.h5 Kf7 55.Kg5 Ng8 56.Kf5 Kg7 57.Ke6 Kh6 58.Kf7 Kxh5 0-1

Knight v Bishop (part 19)

White has just captured in c3 in Spanton (140) - M Lindley (126), Yorkshire League Division 2 1980. Who stands better, and by how much?

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Black is winning, according to the analysis engines Stockfish12 and Komodo11.01.

30...Kd7 31.Kd2 Kc6 32.Be5?

I do not know what my idea was, but I do know it is not a good one.

32...Nxe5 33.dxe5 b5 34.Ke3 Kd7 35.g5 g6 36.g4 Ke6 37.Kd4 a5 38.h4 a4 39.h5 e3?!

Black is still winning after this, but simpler is 39...Kd7 40.h6 (40.Kxd5 e3) Ke6 etc.

40.Kxe3 Kxe5 41.Kf3?

This is hopeless, but 41.h6, although more challenging, also loses, eg 41...Ke6 42.Kd4 Kd6 43.Ke3 Ke5 44.Kd3 Kf4 45.Kd4 Kxg4 46.Kxd5 Kxg5 47.Kc5 Kf5 48.Kxb5 g5 49.c4 Ke6 50.c5 (50.Kb6 is met by 50...g4 as Black will queen with check unless White spends another tempo moving his king) Kd7 51.Kc4 Kc6 52.Kd4 g4 53.Ke3 Kxc5 etc.

41...d4 42.cxd4+ Kxd4 43.Kf4 b4 44.hxg6 hxg6 0-1

Knight v Bishop (part 18)

THERE were 17 bishop-v-knight endings from my praxis that began with seven pawns aside but did not end in draws. The knight's side won nine times.

I now move to bishop-v-knight endings from my praxis that began with six pawns aside but did not end in draws.

Black has just captured on g5 in Tom Musgrave (?) - Spanton (-), Doncaster & District Swiss 1980. Who stands better, and by how much?

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The analysis engines Stockfish12 and Komodo11.01 reckon the position is dead-equal.

34.Nf4 Bd2?

This lets the knight enter the black position and get at the black pawns. The simple 34...Kf6 is among several moves maintaining equality.

35.Ne6+ Kh4?!

The engines much prefer defending the kingside with 35...Kf6. After 36.Nd8 and Nxb7, White is a pawn up but there is a long way to go before that can be converted into a win.

36.Nxg7 Kxh3 37.Nf5

Black has not yet lost a pawn, but the black king is sidelined and the white knight cannot be stopped from raiding the queenside.

37...Bc1 38.b3

The engines' 38.b4!, overprotecting c5, is better, as will become clear.

38...Kh2

The engines give 38...a6!, covering b5. Then 39.Nd6 Bb2 40.Nxb7 Bxd4 requires White to play 41.b4 (this is why 38.b4! is better than 38.b3, even though it puts a pawn on the same colour complex as the bishop). Then 41...Bc3 42.a3 Bb2 43.a4 Bc3 is level. It may be that 43.Nd8 Bxa3 44.Nxc6 is an improvement for White, but 38...a6 is Black's best chance.

39.Nd6 Bb2 40.Nxb7 Bxd4 41.b4 Bc3 42.a3 Bb2 43.a4 d4

If 43...Bc3, White has 44.b5, which would not be so strong if Black had played 38...a6!

The game finished:

44.Na5 d3 45.Nc4 Bc3 46.b5 cxb5 47.axb5 d2 48.Kd2 d1=Q+ 49.Kxd1 Kg3 50.c6 Kxg4 51.c7 h5 52.c8=Q+ Kg5 53.Qg8+ Kh6 54.Qe6+ 1-0