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| May-17-17 | | mel gibson: The computer says:
29. Rh8+ (29. Rh8+ (♖h1-h8+ ♔g8xh8 ♗e3-d4+
c5xd4 ♕e8xe2 ♖f3-f4 f2-f3 ♗f8-h6 ♕e2-e1 ♔h8-g8) +1.89/22 123) score for white +1.89 depth 22 |
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| May-17-17 | | malt: 29.Rh8+ K:h8 30.Bd4+ cd4 31.Q:e2 |
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| May-17-17 | | Iwer Sonsch: Material is equal.
Black's queen is unguarded.
29.Rh8+ Kxh8 (forced) 30. Bd4+ cxd4 31.Qxe2 wins material and looks positionally favourable, e.g. threatening Rh1+ or Qxf3. |
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| May-17-17 | | Iwer Sonsch: Nailed it. |
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| May-17-17 | | 7he5haman: Interesting to note that, <if it were Black to move> in the diagrammed position, Black would have a lovely forced mate, with the main line beginning: <1...Rg3+! 2.Kh2 Rh3+!> 3.Kxh3 Qf3+ 4.Kh4 g5+! |
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| May-17-17 | | 7he5haman: I know this because I thought the puzzle was Black to move... |
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| May-17-17 | | Iwer Sonsch: Stockfish recommends 31...R3f4 32.f3 (2.26 @depth 28). 28...Rf8! would have actually drawn by perpetual. 29.Qxg6!? R8f7 was not a big threat (-0.54 @depth 24). |
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| May-17-17 | | ndg2: My bad, I read "black to play" and found 29..Rg3+ and wins :-) |
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| May-17-17 | | patzer2: Here's my look at today's Wednesday puzzle (29. ?) and game with the chessgames.com opening explorer (OE), Deep Fritz 15 and Stockfish 8: <1. d4 Nf6 2. c4 g6 3. Nc3 Bg7> This is the start of the King's Indian opening (E92) where one of its first successful tests by a GM practitioner was in Black's neat Rook and Pawn endgame win in Flohr vs Geller, 1949. <4. e4 d6 5. Nf3 O-O 6. h3> This is the second most popular move, and has been favored by some strong GMs as evidenced by White's wins
in Carlsen vs Topalov, 2009 and Jakovenko vs Radjabov, 2016. The most popular move is 6. Be2 as in White's win in V Gunina vs P Ladron de Guevara Pinto, 2017 or
Black's win in Gelfand vs Nakamura, 2010. <6... e5 7. d5 a5 8. Bg5 Na6> The moves 6...e5 7. d5 a5 8. Bg5 Na6 are the popular main line (opening theory) replies to 6. h3. <9. Nd2> This solid equalizing move is the second most popular try. It proved itself good for a draw in the games Karjakin vs Nakamura, 2014 and Navara vs Nakamura, 2014. The move most often played, according to the chessgames.com opening explorer, is 9. Be2 as in White's win in W So vs S J Breckenridge, 2017. The third most popular try is 9. g4 as in White's amusing win in R Sturt vs A Vovk, 2017. <9... Qe8 10. Be2 Nd7 11. Nb3> This seldom played move (employed in only 4 games in the OE) should be good for equality according to the
computers.
By far the most popular move here is 11. a3 as in the win by
White, a former world problem solving champion, in K Piorun vs N Georgiadis, 2017. The second most popular move is 11. g4 =, but it hasn't been played much in recent years. In its only appearance in the OE this year, 11. g4 = resulted in a win for Black in C Holt vs S Nagle, 2017. <11... b6 12. h4!?> Our game leaves opening theory as this is the only contest with this move in the OE. The only move previously played here is 12. g4, which resulted in a win for White in
M Lomineishvili vs T Abrahamyan, 2009 and a win for Black in G Margvelashvili vs A Zhigalko, 2008. |
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| May-17-17 | | patzer2: <12... Ndc5 13. Nxc5 Nxc5 14. h5 f5 15. Bf3 fxe4 16. Nxe4 Bf5 17. Qe2 Qa4!?> The computer says this is equal, but Black can do better. A much better choice, which slightly favors Black, is 17... Bxe4! 18. Bxe4 Nxe4 19. Qxe4 Rf5  when play might continue 20. Be3 Rxh5 21. O-O-O Rxh1 22. Rxh1 Bf6 23. Kb1 Qe7 24. Qg4 a4 25. Bc1 a3 26. bxa3 Rf8 27. f3 Qf7 28. Qe4 Qd7 29. Re1 Rb8 30. Re2 Ra8 31. Qc2 Qd8 . <18. Kf1!?> This works well for white in this game, but only because Black overlooks the strong reply 18..h6! to =. Instead, 18. hxg6 Qb4+ 19. Bd2 Qxb2 20. gxh7+ Bxh7 21. Rc1 Qxa2 = is dynamically equal. <18... Qb4?!> This slightly favors White, and more importantly overlooks an opportunity to gain a slight edge for Black with 18... h6! when play might continue 19. Bc1 g5 20. g4 Bxe4 21. Bxe4 Rae8 22. Bg6 to =. <19. Nxc5 bxc5 20. g4 Bc2 21. Qxc2 Rxf3 22. Kg2 Raf8 23. Be3 e4 24. hxg6 hxg6 25. Qxe4 Qxb2 26. Raf1 Qe2 27. Qe6+ R8f7> Black has done a good job so far in keeping the position level. <28. Qe8+ Bf8??> In trying to hold a difficult position, Black slips and makes a decisive blunder. Instead, the second
player can keep it level with 28... Rf8 29. Qe6+ R8f7 30. Qe8+ Rf8 31. Qe6+ = with a draw by repetition. <29. Rh8+!> This solves the Wednesday May 16, 2017 chessgames.com puzzle. The weak "discovered attack" 29. Bd4 ?? allows Black to turn the tables and win after 29...Rxf2+ 30. Rxf2 (30. Kg3 Rg2+ 31. Kh3 Qxg4#) (30. Kh3 Rh7+ 31. Kg3 Qf3#) (30. Kg1 Rg2#) 30... Rxf2+ 31. Bxf2 (31. Kg3 Rg2+ 32. Kf4 Rxg4#) (31. Kh3 Qf3+ 32. Kh4 Qxh1+ 33. Kg5 Qh6#) 31... Qxe8  . <29... Kxh8 30. Bd4+ cxd4> If 30... Kg8 then simply 31. Qxe2  wins. <31. Qxe2 d3?> This makes the win too easy for White. Instead, Black can put up considerable resistance with 31... R3f4 when according to the computer White's best chance at securing the win is with 32. f3  to (+2.64 @ 38 depth, Stockfish 8.) However, despite the favorable evaluation by the computer, finding the precise moves to secure a win OTB would prove extremely difficult. <32. Qxf3 1-0> Black resigns in lieu of 32...Rxf3 33. Kxf3 Bh6 34. Ke4 d2 35. Rd1 Kg7 36. f4 . |
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| May-17-17 | | Monocle: <ChessHigherCat: Maybe I'm missing something but I think my line is much better than the game line. What's my line? 29. Rh8+, Kxh8, 30. Rh1+ Kg7, 31. Bh6+ Kf6. 32. Qxd2 Bxh6 33. Rxh6> Not sure why Black would play 30... Kg7 instead of just going back to g8. |
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| May-17-17 | | whiteshark: <patzer2: The weak "discovered attack" <29. Bd4> ?? allows Black to turn the tables and win after 29...Rxf2+ 30. Rxf2 (30. Kg3 Rg2+ 31. Kh3 Qxg4#) (30. Kh3 Rh7+ 31. Kg3 Qf3#) (30. Kg1 Rg2#) 30... Rxf2+ 31. Bxf2 (31. Kg3 Rg2+ 32. Kf4 Rxg4#) (31. Kh3 Qf3+ 32. Kh4 Qxh1+ 33. Kg5 Qh6#) 31... Qxe8 .> Now that does answer my unsaid question. |
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| May-17-17 | | clma55: Why not Bd4 with checkmate in h8¿. Dont need the rook sacrifice |
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| May-17-17 | | Walter Glattke: 32.Qf3 needs a new stockfish analysis, see: 32.-Rxf3 33.Kxf3 Bh6 34.Rh1 Kg7 35.Ke2 d2 36.a4 Bg5 37.f3 a5 won ending!? Not more than one stockfish point for white, I think. |
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| May-17-17 | | swclark25: Agreed with game line thru 32)Qxe2. I do wonder if Black's 32)...d3 followed by White's 33)Qxf3 is best for either? Why does Black resign? Seems 33)...Rxf3 34)Kxf3 leaves Black with Bishop+5P and White with Rook+5P. Is this clearly won for White at this point? |
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| May-17-17 | | Walter Glattke: I had a quick test with Rb1, where Bf4 holds Pg5, Pd2, and Pd6 for a while, then Bxa7 Rxa7 and Kd1 and rook stops black king with g-pawn breakthrough try. |
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| May-17-17 | | NBZ: Yeah agree with patzer2 that d3 is really strange, and R3f4 was definitely worth a shot. (Perhaps Black was still reeling from the fact that he had just blundered in a decent position.) In fact it's drawn without the a-pawns; Black's problem is he probably cannot hold on to the a-pawn, and if White gets a passed a-pawn, he should surely win. But let's look at some lines. 31. .. R3f4 32. f3
White is of course threatening Qd2 and Qxa5. How about:
32. ... Bg7 33. Qd2 d3!?
click for larger view |
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| May-17-17 | | NBZ: I posted my last comment too early. The point is that after 34. Qxd3 (which is by no means forced) Bd4 35. Qd2 Bb6 Black has locked down the position and now can make things hard for White. 
click for larger viewIf White now tries 36. Qc3+ Kg8 37. Rh1 Black has defences like 37. ... Rd4. I think it would be irresponsible for White to allow Black to get a defense like this going, but this was Black's best shot I think. |
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| May-17-17 | | NBZ: Final thought: even in the last position, it looks to me like White can put his Q on the c-file, play c5! at an opportune moment, forcing Black to lock his bishop out of the game with dxc5, and then use the queen and rook to hunt the king (basically Q+R vs R+R). Still that will take some technique and who knows when the bishop might spring out of its trap. |
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May-17-17
 | | PawnSac: < clma55: Why not Bd4 with checkmate in h8? Dont need the rook sacrifice > After 29. Bd4? Rxf2+! 30.Rxf2 Rxf2+ 31.Bxf2 Qxe8 (if 31.Kg3 Rf3+ 32. Kh4 Qxe8 or if 30.Kg3 R7f3+ and 31...Qxe8) |
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| May-17-17 | | Iwer Sonsch: <NBZ> Even without the A pawns, Stockfish 7 still sees a 1.63 advantage for White after 31...R3f4 32.f3! (depth 28). |
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| May-17-17 | | patzer2: I was suspicious that Stockfish 8 had not really found a win for White after the improvement 31...R3f4 32. f3! despite a near plus three evaluation at 38 depth. So I ran the program for over 6 hours on 31...Ref4 32. f3! to 42 depth and it came up with the following best play line which does not provide a decisive result for White: 31...R3f4 (improving on 31...d3?) 32.f3! Be7 33.Qe1 d3 34.Rh1+ Kg7 35.Qe3 Bg5 36.Qxd3 Bf6 37.Qe3 Be5 38.Rh3 Rf8 39.c5 Ra8 40.cxd6 cxd6 41.Qc1 Raf8 42.Kf2 a4 43.Ke2 Rh8 44.Rxh8 Kxh8 45.Qc7 Kg8 46.Ke3 Rd4 47.Qc2 Kg7 48.g5 Rf4 49.a3 Rh4 50.Qc7+ Kg8 51.Qc8+ Kg7 52.Qd7+ Kg8 53.Qe6+ Kg7 54.Qe7+ Kg8 55.Qc7 Bf4+ 56.Ke2 Be5 57.Qd8+ Kg7 58.Qe7+ Kg8 59.Qe6+ Kg7 60.Qd7+ Kf8 61.Qe6
( +2.30 @ 42 depth, Stockfish 8 x 64)
Matter of fact, when I had Stockfish assess just the final position in this analysis (diagram below after 61. Qe6 in above analysis) 
click for larger view the program gave it a draw evaluation after Black's next move 61...Kg2 = (0.00 @ 32 depth, Stockfish 8 X 64) That's not to say that there are not improvements in this line that would give the win to White. However, what it does indicate is that the win, if it truly exists for White after 31...R3f4!?, would be extremely difficult -- especially under time pressure over the board. |
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| May-17-17 | | stst: Late but quick: idea? + and QxQ
29.Rh8+
if (A)29.....Kg7, 30.Bh6+ KxR, 31.QxQ
if (B)29.....KxR, 30.Bd4+ cxB (or Q e5 intervenes, BxQ) 31.QxQrest should be easy for W. |
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| May-17-17 | | stst: <29.Rh8+ Kxh8 (forced) ...> Inaccurate... not forced, Kg7 is possible, though outcome the same, Black's Q lost after B+ |
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| May-18-17 | | ChessHigherCat: .<Monocle: <ChessHigherCat: Maybe I'm missing something but I think my line is much better than the game line. What's my line? 29. Rh8+, Kxh8, 30. Rh1+ Kg7, 31. Bh6+ Kf6. 32. Qxd2 Bxh6 33. Rxh6> Not sure why Black would play 30... Kg7 instead of just going back to g8.> <Cybe> already pointed that out. I was just calculating in my head late at night so it was combination of wishful thinking and sleep deprivation. |
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Kibitzing
sac: 29.Rh8+