| Sep-16-22 | | jrredfield: i looked at 22 f5, 22 Rfb8 and 22 Rxb8. I had a feeling it was f5 but I didn't see it far along sufficiently to be certain so I can't claim credit. After 22 f5, Black can either priortize stopping the pawn advance and inevitably lose a rook or in this case, allow the pawn advance and become defenseless. Komodo Dragon prefers the text move by a significant margin. White +11.47 (depth 37): 22.f5 ♘f6 23.fxg6 hxg6 24.gxf6 ♖xb7 25.♕c8+ ♔f7 26.fxe7+ ♔xe7 27.♕xf8+ ♔d7 28.♕f7+ ♗e7 29.♘f4 g5 30.♘g6 ♕e3 31.c4 ♖b2 32.♕f5+ ♔c7 33.♘xe7 ♕xe7 34.cxd5 c5 35.d6+ ♕xd6 36.♕f7+ ♕d7 37.♕f6 ♖xg2 38.♔xg2 ♕d2+ 39.♕f2 ♕d5+ 40.♕f3 ♕a2+ 41.♔h1 ♔b6 42.♕f6+ ♔b5 43.♕f5 a6 44.♖c1 ♕a3 45.♕xg5 ♕xh3+ 46.♔g1 ♕c8 47.♕g6 ♕c6 48.♖b1+ ♔c4 49.♕c2+ ♔d4 50.♖d1+ ♔e5 51.♕h2+ ♔e4 52.♕h4+ ♔f3 53.♖f1+ |
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| Sep-16-22 | | Brenin: White is 2P down with a R en prise. Press on with 22 f5, since 22 ... Rxb7 allows 23 Qc8+ Kf7 24 fxg6+ Kxg6 25 Qxf8 and Black's exposed K will not survive long. Black can decline the R, e.g. 22 ... gxf5 but then 23 Rxb8+ Bxb8 24 Qc8+ Kf7 25 Qxf5+ wins. |
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| Sep-16-22 | | actinia: I also saw 22. f5 and didn't calculate every last line, since it wins at least a piece with a continuing attack by white's active pieces against a very exposed black king |
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| Sep-16-22 | | mel gibson: I got the wrong answer today.
I chose the simpler 22. Rxb8+
with the idea of swapping off Rooks.
Stockfish 15 agrees with the text and says:
22. f5
(22. f5 (f4-f5 ♘g8-f6 f5xg6 h7xg6 ♖b7xb8+
♗d6xb8 g5xf6 ♔e8-d8 ♘e2-d4 ♖f8xf6 ♕e6xf6 e7xf6 ♘d4-e6+ ♔d8-e7 ♘e6xc5 ♗b8-c7
♘c5-d3 a7-a5 ♖f1-e1+ ♔e7-f7 ♖e1-b1 ♔f7-e6 ♖b1-b7 ♗c7-d8 ♖b7-a7 g6-g5 ♖a7-a6
♔e6-d6 ♗g2-f3 ♔d6-d7 ♗f3-g4+ ♔d7-d6 ♖a6-a7 ♗d8-c7 ♔h1-g2 d5-d4 ♖a7-a6
♗c7-d8 ♗g4-f3 f6-f5 ♖a6xc6+ ♔d6-d7 ♖c6-a6 ♔d7-e7 ♔g2-h1 ♔e7-e8 ♗f3-d5 g5-g4
h3xg4 f5xg4 ♘d3-c5 ♗d8-c7 ♘c5-e6 ♗c7-b8 ♘e6xd4 ♔e8-e7 ♖a6-e6+ ♔e7-f8 ♖e6-g6
♗b8-c7 ♖g6-a6 ♗c7-b8 ♘d4-f5) +10.02/41 789)
score for White +10.02 depth 41.
When I force Stockfish to play my choice it still wins but it's a much weaker move: 22. Rxb8+
(22. Rxb8+ Bxb8 (♗d6xb8 c2-c4 ♕c5-d6 c4xd5
♘g8-f6 g5xf6 ♕d6xe6 d5xe6 ♖f8xf6 ♗g2xc6+ ♔e8-f8 ♗c6-d7 ♔f8-g7 ♔h1-g2 ♖f6-f5
♔g2-f3 ♖f5-h5 ♖f1-h1 ♖h5-h4 ♔f3-e4 ♗b8-d6 ♖h1-d1 ♗d6-b4 ♖d1-d3 ♔g7-f6
♖d3-f3 a7-a5 ♘e2-d4 g6-g5 ♘d4-e2 a5-a4 ♗d7xa4 ♔f6xe6 ♔e4-d3 ♗b4-a3 ♘e2-d4+
♔e6-f6 f4xg5+ ♔f6xg5 ♖f3-e3 ♔g5-f6 ♖e3-e6+ ♔f6-f7 ♗a4-b3 ♔f7-e8 ♖e6-e3
♖h4-f4 ♖e3-g3 ♔e8-d7 ♗b3-d5 ♗a3-b2 ♘d4-f3 ♖f4-f5 ♗d5-e4 ♖f5-h5 ♔d3-e3
♗b2-c1+ ♔e3-f2 ♗c1-f4 ♖g3-g4 ♗f4-d6 ♔f2-g2 h7-h6 ♘f3-d4 ♖h5-a5 ♗e4-f5+
♔d7-c7 ♘d4-e6+ ♔c7-b6) -3.60/49 706)
score for Black -3.60 depth 49. |
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Sep-16-22
 | | al wazir: The game line isn't forced:
22...Rxb7 23. f6 Nxf6 24. gxf6 Rxf6 25. Qc8+ (25. Rxf6 Rb1+ 26. Bf1) Kf7 26. Rxf6+ (26. Qxb7 Rxf1+ 27. Bxf1 Qf2) exf6 27. Qxb7+ Be7. Black has four ♙s for the ♘.
But 23. Qc8+ Kf7 24. fxg6+ Kxg6 25. Qxf8 Rb8 (25...Be5 26. Qf7+ Kxg5 27. Rf5+ Kh4 28. Qh5#) 26. Qf7+ Kxg5 27. Qg7+ Kh5 28. Bf3+ finishes black off. |
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| Sep-16-22 | | raymondhow: Got the first move 22.f5 then wanted to play 23.fxg6, thought I had missed when the game went 23.gxf6. But the engine likes my move better, so think I get to count that as a solve. |
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| Sep-16-22 | | parch: After looking at 22.R:b8 B:b8 23.Rb1
Went for 22.f5 opening the King's side. 22...gf5(22...R:b7 23.Qc8+ Kf7 24.fg6+ K:g6 25.Q:f8 )
24.R:b8+ B:b8 25.Qc8+ Kf7 26.Q:f5+ Nf6 27.gf6 ef6 divided on 28.Q:f6+ or 28.Rb1 winning. |
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Sep-16-22
 | | chrisowen: Irk darks quandary mates v it wet f5 feint duffy axiom jeeps aileron offer it f5 aka; |
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| Sep-16-22 | | saturn2: You start with 22 Rxb8 Bxb8 23.Qc8+ (trying to win the Bb8) but after Kf7 the Bb8 is protected and the Rf8 even attacks the queen.
Then you think how nice it would be to have an open f file.... |
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| Sep-16-22 | | saturn2: If black does not want to lose the bishop on b8 a possible line is 22.f5 Rd8 23.f6 Rf7 24.Qxf7+ Kxf7 25.fxe7+ |
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| Sep-16-22 | | TheaN: It took me a while to see all variations, but I did and it's a satisfying Friday puzzle: White breaks through decisively with <22.f5!> and Black is helpless because both rooks and the knight on g8 are crucial targets. The 'obvious' is 22....Rxb7 23.Qc8+ Kf7 24.fxg6+, where the doublecheck puts Black in a heap of trouble, 24....Kg7? 25.Qxf8+ Kh8 26.g7#, and 24....Kxg6 25.Qxf8 +- and White managed to infiltrate with major pieces. Simply ignoring Pf5 is not an option, as for example 22....Rd8 23.f6! +- and White will use pawns rather than rooks to finish Black off. What Black played, 22....Nf6, is an interesting try to bring the misplaced piece back, but it doesn't really do much. Both 23.gxf6 and 23.fxg6 +- lead to huge advantages for White. Then lastly is taking on f5: 22....Rxf5 is somewhat unfortunate as this opens up the f-file fatally: 23.Qxg8+ Rf8 24.Rxf8#. The critical line is <22....gxf5>, but now the f-file is essentially semi-open, White just has to be careful when to take on f5: <23.Rxb8+ Bxb8 24.Qc8+ Kf7> first, and now <25.Qxf5+ +-> is curtains. |
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| Sep-16-22 | | TheaN: 
click for larger view
The possible checkmate after 22....Rxb7 23.Qc8+ Kg7 24.fxg6+ Kg7 25.Qxf8+ Kh8 26.g7#. Chess can be a game of wonders. |
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| Sep-16-22 | | agb2002: White is two pawns down.
Black threatens to simplify the position with Rxb7. The first idea that comes to mind is 22.f5 to incorporate the rook on f1 into attack: A) 22... Rxb7 23.Qc8+ Kf7 24.fxg6+
A.1) 24... Kxg6 25.Qxf8
A.1.a) 25... Rb8 26.Qf7+ Kxg5 27.Rf5+ Kh6(4) 28.Rh5#. A.1.b) 25... Nf6 26.Rxf6+ exf6 (else 27.Qh6#) 27.Qxf6+ Kh5 28.Qh6#. A.1.c) 25... Qxc2 26.Qxg8+ Kh5 27.Bf3+ Kh4 28.Qe6 Kxg5 (28... Qg6 29.Qg4#) 29.Rg1+ and mate in two. A.2) 24... Kg7 25.Qxf8+ Kxg6 (25... Kh8 26.g7#) 26.Qxg8+ Kh5 27.Bf3+ Kh4 28.Qxh7#. B) 22... Rf5 23.Qxg8+ Rf8 24.Q(R)xf8#.
C) 22... Qxc2 23.Rxb8+ Bxb8 24.fxg6+ Kg6 (24... Kg7 25.Qxf8+ as in A.2) 25.Qxf8 wins decisive material (25... Qxe2 26.Qxg8+ wins). D) 22... gxf5 23.Rxb8+ Bxb8 24.Qc8+ Kf7 25.Rxf5+ Nf6 (25... Kg7 26.Qxf8+ wins; 25... Kg6 26.Rxf8 wins) 26.Qd7 D.1) 26... B(Q)xd6 27.Rxf6+ wins decisive material. D.2) 26... Kg6 27.gxf6 exf6 28.Nf4+ Bxf4 29.Rxf4 must be winning. For example, 29... h5 30.Qf5+ followed by 31.Be4 is crushing (31... dxe4 32.Qxc5). E) 22... Rd8 23.fxg6
E.1) 23... Rxf1+ 24.Bxf1, with the triple threat Qf7#, Qxg8# and gxh7, wins. E.2) 23... hxg6 24.Qxg6+ Rf7 25.Qxf7#.
E.3) 23... Qxc2 24.Rxf8+ Kxf8 25.Qf7#. |
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| Sep-16-22 | | Brenin: It's a minor quibble, since White is clearly winning anyway, but after 22 f5 Rd8 I think 23 fxg6 (<agb2002>'s line E) is stronger than the 23 f6 preferred by some, since the threat of 24 Rxf8+ Kxf8 25 Qf7 mate forces line E1 23 ... Rxf1+ 24 Bxf1 and now 24 ... Qf2. This last move avoids the mates by White on f7 and g8, and also threatens 25 ... Qh2 mate and 25 ... Qxf1+. However, White has 25 Qxg8+ Qf8 26 gxh7 Be5 (preventing 27 h8=Q) 27 Nf4 (threatening 28 Ne6) Rd6 28 Rb8+, winning the house. |
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| Sep-16-22 | | TheaN: <Brenin: It's a minor quibble, since White is clearly winning anyway, but after 22 f5 Rd8 I think 23 fxg6 (<agb2002>'s line E) is stronger than the 23 f6> Nope! 23.f6 #8 23.fxg6 #11. I made SF analysis that long enough to ply out every possibility in a 22-ply (given fxg6 is mate in 11). Your line in the fxg6 line is correct, but f6 is faster because of the f7+ threat. SF instantly starts throwing pieces (23....Bc7 24.Rxc7 etc) to prolong the game. Sensible moves like 23....Nxf6 24.gxf6 Rf7 (this is similar as Rf7 straight away) 25.Qxf7+! Kxf7 26.fxe7 #4. Tl;dr though, 23.f6 is as destructive as 23.fxg6, and objectively faster. |
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Kibitzing
sac: 23.gxf6