| Jun-03-08 | | notyetagm: White to play: 61 ?
click for larger viewHere the Black c6-rook must meet the threat of the White c7-pawn promoting on c8 by
<DEFENDING> the c8-promotion square, so the Black c6-rook cannot leave the c-file.
That is, the <OBLIGATION> of the Black c6-rook to meet the threat of c7-c8=♕+
<RESTRICTS> the <MOBILITY> of the Black c6-rook to the c-file, i.e., the Black c6-rook
does not control -ANY- squares along the 6th rank.
Now consider the White a6-pawn. Is it threatening to do anything? <<<Yes, it is!>>>.
The White a6-pawn is threatening to advance to the a7-square, in which case the
White a7- and c7-passers would simply overwhelm the Black c6-rook. How is Black meeting
this threat, the threat of a6-a7? Is Black <PINNING> the White a6-pawn? No. Is Black
<DEFENDING> the a7-square, like he is <DEFENDING> the c8-square to prevent the advance
of the White c7-pawn? No. <<<Black is meeting the threat of the advance of the White a6-pawn
-ONLY- by <BLOCKADING> it with his own Black a6-pawn!>>>. For the Black a7-pawn to
<BLOCKADE> the White a6-pawn to prevent its advance, the Black a7-pawn must stay on the a7-square.
Hence the <OBLIGATION> of the Black a7-pawn to meet the threat of a6-a7 <RESTRICTS> the
<MOBILITY> of the Black a7-pawn to the a7-blockading square, i.e., the Black a7-pawn -CANNOT- move at all. <<<Now, if the Black c6-rook cannot leave the c-file because it must <DEFEND> the c8-promotion square, and if the
Black a7-pawn must stay on the a7-square to <BLOCKADE> the White a6-pawn, then neither the Black c6-rook nor
Black a7-pawn <DEFENDS> the b6-square, right?>>> So what can we conclude about the number of defenders of the b6-square? There are -ZERO- defenders of the b6-square.
Why? Because both the Black a7-pawn and Black c6-rook have other threats to meet (<OBLIGATION RESTRICTS MOBILITY!>). Hence Volkov (White) played 61 ♘d5-b6! and Hou Yifan resigned immediately. Position after 61 ♘f5-b6! 1-0
click for larger viewThe White b6-knight has <GAINED CONTROL OF THE PROMOTION SQUARE> (c8-square) of the
White c7-passer. Black will then be forced to give up her rook the pawn. 61 ♘d5-b6! is a lovely tactical shot the wins the game on the spot, based on the tactical point
that both the Black a7-pawn and c6-rook are <OVERWORKED> so that neither <DEFENDS> the b6-square. |
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| Jun-03-08 | | syracrophy: 61.♘b6!! |
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| Jun-16-08 | | notyetagm: White to play: 61 ?
click for larger view<syracrophy: 61.Nb6!!> Yes, a great move, winning on the spot.
click for larger view |
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| Jan-07-09 | | notyetagm: Boy how I do love Volkov's 61 ♘d5-b6! move. |
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| Mar-05-09 | | notyetagm: Game Collection: Blockaders do not defend squares S Volkov vs Yifan Hou, 2008
61 ?
click for larger view
61 ♘d5-b6! 1-0
click for larger view |
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| Apr-22-11 | | notyetagm: Game Collection: Blockaders do not defend squares |
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| Apr-22-11 | | notyetagm: Game Collection: !! --: A square only appears multiply defended |
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| Apr-24-11 | | notyetagm: Game Collection: BLOCKADERS DO *NOT* PROTECT SQUARES!!! Spassky vs Larsen, 1969 67 Qc8xRe6! 1-0 S Volkov vs Yifan Hou, 2008 61 Nd5-b6! 1-0 Topalov vs S Zhigalko, 2008 39 Rd1xd5!! |
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| May-24-11 | | cyclemath: Black is probably lost even with best play at White's 46th, but after 46 ... Re7, the response 47 Re2 would surely have secured instant resignation. |
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Mar-11-19
 | | wood n tempo: Volkov Cocktail |
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| Oct-10-19 | | Cheapo by the Dozen: I deviated at Move 56 with Rh8, which according to the engine wins a little less thumpingly than the game move, which in turn is a little less crushing than the engine's favorite, Bd6. Anyhow, the basic idea of sacrificing the exchange, oops it's a sham sacrifice because White forks another piece, oops it's a real sacrifice again because White has a piece en prise, oops White wins big anyway because of his advanced pass pawn -- well, that part was really easy to find. :) |
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| Oct-10-19 | | Walter Glattke: 53.Rd8+ Kf7 54.Bf4 Rec3 55.Nb4 Rxa5 56.Nd5 Rc1 57.Ne3 Ke6 58.Nxf5 gxf5 59.Rxc8 seems to be more easy |
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| Oct-10-19 | | Walter Glattke: 57.-Be6! |
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| Oct-10-19 | | saturn2: I saw 53. Rxf5 gxf5 54. Rd8+ Kf7 55. Rxc8 Rac3 like in the game and then 56. Bf2 (to block the c file by Bc5)
Re8 57. Rd8 Rc6 58. Bxa7 Rxa6 59.Bb6. This should win. |
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| Oct-10-19 | | karik: <notyet> really seems to have had multiple orgasms with 61.Nd5-b6 |
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| Oct-10-19 | | mel gibson: This was a tough one - so many things to consider. Stockfish 10 agrees with the text move.
53. Rxf5
(53. Rxf5 (♖d5xf5 g6xf5 ♖d2-d8+
♔g8-f7 ♖d8xc8 ♖a3-c3 ♗g3-d6 ♖c3-c6 ♖c8-f8+ ♔f7-g6 ♖f8-g8+ ♔g6-f7 c7-c8♕
♖c6xc8 ♖g8xc8 ♖e3-e4 ♖c8-c7+ ♔f7-f6 ♔h2-g3 ♖e4-d4 ♗d6-e7+ ♔f6-e5 ♖c7xa7
f5-f4+ ♔g3-h2 ♖d4-d2 ♗e7-g5 ♖d2-b2 ♘a6-c5 ♔e5-d5 ♘c5-d3 ♖b2-b8 ♘d3xf4+
♔d5-c6 ♘f4xh5 ♖b8-b2 ♘h5-g7 ♖b2-b5 ♗g5-f4 ♖b5-b2 ♗f4-e5 ♖b2-b4 ♗e5-g3
♖b4-b3 ♘g7-e6) +13.69/42 304)
score for White +13.69 depth 42 |
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Oct-10-19
 | | OhioChessFan: I had <Cheapo's> 56. Rh8 line. |
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| Oct-10-19 | | Whitehat1963: Nope! Just nope. Not even close. |
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| Oct-10-19 | | malt: Went for 53.R:f5 gf5 54.Rd8+ Kf7 55.R:c8 Rac3 56.Ra8
and if ...R:g3 57.c8/Q
Nice finish 61.Nb6! |
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| Oct-10-19 | | TheaN: This defender munching is a clear candidates, and by proxy, the only real one. White can probably turn it around with 53.Rd8+ first, but <53.Rxf5!> forces Black's hand. A) 53....Rxg3, counterattacking is flawed here, 54.Rd8+ Kg7 55.Rxc8 and with just the rooks on the board Black has no claim whatsoever: 55....gxf5 (what else?) 56.Rg8+ Kxg8 57.c8=Q+ +- should be an easy convert for White. B) 53....Ne7, the only reasonable move to keep enough tabs on c8 (Nb6 axb6, Nd6 Bxd6) but now the bishop speaks: 54.Rd8+ Kg7 (Kh7 55.Rf7+ Kh6 56.Rh8#) 55.Be5+ Rxe5 (K 56.Rh8#) 56.Rxe5 +- and demise. C) So, 53....gxf5 54.Rd8+ Kf7 (no reason to go to the corner or a dark sqaure and this defends e8) 55.Rxc8. Now, 55....Rxg3? still runs into 56.Rf8+ +- at least, so 55....Rac3. At this point, I acknowledged +- and stopped. Though perhaps a move too soon, a lot of White moves win here, the pieces are incredibly strong and the Black rooks are just spectators. 56.Rd8, Rh8, Ra8, Bd6, Bf2!? are all +- with an advantage of at least +5. Even 56.Nc5?! wins. Done deal, pieces in the box. |
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| Oct-10-19 | | patzer2: In attempting today's Thursday puzzle (53. ?), I got the first four moves of the game continuation (i.e. 53. Rxf5 gxf5 54. Rd8+ Kf7 55. Rxc8 Rac3 56. Rd8 +-). However, after 56...Rd8 I had a Stan Laurel and Oliver Hardy moment (see https://video.search.yahoo.com/yhs/...), thinking "this is another nice mess you've gotten us into" as I struggled to find a winning continuation for White. I wished I had found the clever game continuation 57. Nb4! +- (+10.64 @ 33 ply, Stockfish 10) or the computer best move 57. Bd6 +- (+11.06 @ 33 ply, Stockfish 10). Instead, the best I could do was 57. Bf2 +- (+9.00 @ 32 ply, Stockfish 10) which fortunately for me is still winning. P.S.: Black's game went bad early in this game with 17...Qd7?, allowing 18. e6! ± to +- (+1.63 @ 33 ply, Stockfish 10). Instead, 17...Qe7= (+0.09 @ 33 ply, Stockfish 10) would've held the game level. |
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Oct-10-19
 | | agb2002: White has an extra pawn.
Black threatens Rxg3.
The black bishop controls the promotion square of the c-pawn. This suggests 53.Rxf5: A) 53... gxf5 54.Rd8+
A.1) 54... Kf7 55.Rxc8
A.1.a) 55... Rxg3 56.Rf8+ Kxf8 (else 57.c8=Q wins) 57.c8=Q+ Ke(f,g)7 58.Qc7+ followed by 59.Qxg3 ends up a knight ahead. A.1.b) 55... Rac3 56.Rd8 followed by c8=Q wins decisive material. A.1.c) 55... Rxa5 56.Rf8+ followed by c8=Q wins decisive material. A.2) 54... Kg(h)7 55.Rxc8 Rxg3 (else as above) 56.Rg(h)8+ Kxg(h)8 57.c8=Q+ Kh7 (else as above) 58.Qxf5+ A.2.a) 58... Kg7 59.Qe5+ followed by 60.Qxg3 as in A.1.a. A.2.b) 58... Kh6 59.Qf4+ followed by 60.Qxg3 as in A.1.a. A.2.c) 58... Kh8 59.Qxh5+ wins decisive material. A.2.d) 58... Rg6 59.Qxh5+ as above.
B) 53... Rxg3 54.Rd8+ Kg7 (54... Kh7 55.Rf5+ Kh6 56.Rh8#) 55.Rxc8 gxf5 56.Rg8+ transposes to A.2. |
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| Oct-10-19 | | Chesgambit: amazing |
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| Oct-10-19 | | TheBish: Got the solution (which was pretty easy) and the improvement of 56. Bd6! (also the engine's choice), which is a cleaner and easier win. |
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| Oct-10-19 | | NBZ: <TheBish>: 56. Bd6! is indeed nice. I am glad White did not play it though, because we then got treated to the corking 61. Nb6!! later. |
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Kibitzing
sac: 53.Rxf5