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< Earlier Kibitzing · PAGE 6 OF 6 ·
Later Kibitzing > |
Jul-07-09
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| Pawn and Two: <CharlesSullivan> In my last post, in the 4th paragraph, I included a line from Fritz after 42.Bf7. I will wait with additional analysis until I review your findings. |
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| Jul-07-09 |
| CharlesSullivan: <Pawn and Two> Oops! Yes you did! So far Rybka 3 is showing 42.Bf7 b2 43.Ba2 Rh5 (in agreement with Fritz) but evaluates this as completely equal. However, I'm continuing to analyze this. In the meantime, here is further analysis from my post of July 4th... <Position after 38...Rxa2! 39.Rh8 b3 40.h5 Rc2 41.h6 Rc5 42.Bf3 b2 43.h7 b1=Q 44.Rc8 Qb2 45.h8=Q Qxh8 46.Rxh8 Na7 47.d4 Ra5 48.Rh6+ Kc7 49.d5 Nb5 50.Rc6+ Kd8 51.Bg4 a3 52.d6 Ra8 53.d7 Nc7 54.Rh6 Ke7 55.Rh7+ Kd6 56.Rh1 Ke7 57.Bf3 Ra6>
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<VARIATION 1> Suppose Black allows White to achieve what seems to be an ideal position: 58.Rh7+ Kd8 59.Bg4 Rd6 60.Rh8+ Ke7 61.Rh1 a2 62.Bf5 Kd8 63.Ra1 Ra6 64.g4 Ra5 65.Kg3 Ke7 (even better is 65...Ra3+) 66.Kf3 Ra3+ 67.Ke4 Ra4+ 68.Ke5 Ra5+ 69.Kf4 Nd5+ 70.Kg5 Kd8 <White has 2 extra pawns, but...>
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But despite the material advantage, I have not been able to find a win for White. <VARIATION 2> This variation is even more critical for Black: 58.Bb7 Rb6 59.Bc8 Rd6 60.Ra1 Rd3 61.Kh3 Kd8 62.Kh4 Ne6 63.g4 Rf3 64.Ra2 Rc3! 65.g5 Rc4+! 66.Kh5 Rc5 67.Rxa3 Rxg5+ 68.Kh6 Rg2 69.Rf3 Rh2+ 70.Kg6 Rg2+ 71.Kh5 Rh2+ 72.Kg4 Rg2+ 73.Kh4 Rh2+ 74.Kg3 Rh8 75.Kg4 Rg8+ 76.Kh5 Kc7!! 77.Rf6 Rh8+ 78.Kg6 Nd8 79.f4 Rg8+ 80.Kh6 Rg1 81.f5 Rf1 82.Rf8 Rd1 <White is obviously better...>
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83.Re8 Rf1 84.Kg6 Rg1+ 85.Kf6 Ra1 86.Rg8 Nc6 87.Rf8 Rd1 88.Re8 Nd8 89.Re2 Rg1 90.Rc2+ Kd6 91.Rh2 Kc7 92.Rh5 Rg8 93.Rg5 Rf8+ 94.Kg7 Rf7+ 95.Kg6 Rf8 96.f6 <White is even better than before...>
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The computers all see that White's position is superior (+3.58 at least!), but this still seems to be a draw: 96...Rg8+ 97.Kf5 Rh8 98.Rg7 Rh3 99.Re7 Rf3+ 100.Kg5 Rf2 101.Kg6 Nc6 102.Kg7 Rf4 103.Re8 Nd8 104.Re3 Rf2 105.Re7 Nc6 106.Kg6 Rf3 107.Re8 Nd8 108.Re5 Rg3+ 109.Rg5 Rc3 110.Rg1 Rf3 111.Rg4 Kd6 112.Rg2 Kc7 113.Rc2+ Kd6 114.Rd2+ Kc7 115.Re2 Rg3+ etc. <White is stymied!>
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Draw!! Neither of these ridiculously long variations is forced, of course, but they seem to demonstrate that with careful play, Black can draw after 38...Rxa2. |
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Jul-12-09
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| Pawn and Two: <CharlesSullivan> I had Fritz review your analysis of 07/07/09, but it was unable to find a winning continuation for White. I have not done any further analysis of the line, 38...Rxa2 39.Rh8 b3 40.h5 Rc5 42.Bf7. I will wait for your review and comments. The line, 38...Rxa2 39.Rh6 Rc2 40.h5 b3, does not seem to offer White any winning chances. However, the line 38...Rxa2 39.Rh6 Rc2, (.90) (25 ply) 40.g4 a3 41.h5 Rc5 42.Bf7 Ra5, looks very promising for White after 43.Ba2 Rb5 44.Bb3 Ra5 45.Re6. Additional analysis is needed for this line. In this line, 43.d4 Kb7 seems likely to lead to a draw. After 43.d4 Kb7, early analysis indicates 44.Ba2 may be White's best try. Also, as noted in my post of 07/06/09, additional analysis is needed for the lines: 38...Rxa2 39.Rh8 Rd2, and 38...Rxa2 39.Rh8 Rc2. The truth about 38...Rxa2! has eluded chess analysts for nearly a century! At times I think we have the answer, but then the sands shift, and it was only another illusion. |
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Jul-12-09
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| Bridgeburner: <The truth about 38...Rxa2! has eluded chess analysts for nearly a century!> Pity the poor sods that have to figure it out over the board! |
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Jul-12-09
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| Pawn and Two: <CharlesSullivan> While promising on first review, additional analysis of the line, 38...Rxa2 39.Rh6 Rc2 40.g4 a3 41.h5 Rc5 42.Bf7 Ra5 43.Ba2 Rb5 44.Bb3 Ra5 45.Re6, indicates that Black can obtain a draw: (1.29) (26 ply) 45...a2 46.Bxa2 Rxa2 47.h6, (.82) (26 ply) 47...Ra8 48.g5 b3 49.h7 b2 50.Re1 Rh8, (.69) (26 ply) 51.f4 Rxh7 52.Rb1 Kc5 53.Rxb2 Nb4 54.d4+ Kc4 55.Kf3 Rg7, (.17) (24 ply) 56.Rd2 Nd5 57.Rc2+ Kxd4 58.Ra2 Rg8, resulting in an equal position. It now seems likely that 38...Rxa2 39.Rh6 only leads to a draw. |
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| Jul-14-09 |
| CharlesSullivan: <Pawn and Two> wrote: <While promising on first review, additional analysis of the line, 38...Rxa2 39.Rh6 Rc2 40.g4 a3 41.h5 Rc5 42.Bf7 Ra5 43.Ba2 Rb5 44.Bb3 Ra5 45.Re6, indicates that Black can obtain a draw: (1.29) (26 ply) 45...a2 46.Bxa2 Rxa2 47.h6, (.82) (26 ply) 47...Ra8 48.g5 b3 49.h7 ...> But I believe that 49.Re1 (sacrificing the strong h-pawn with 49.h7 does not seem right, although computers like it!) leads to a winning game for White: <Black to move, but Black is lost>
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(A) 49...Rh8 50.Kg3 Kc5 51.f4 Kb4 52.Kg4 b2 53.Kh5 Nd4 54.g6 winning position (B) 49...Nd4 50.h7 Nf5 51.Kh3 Kc5 54.Kg4 Nh6+ 53.Kh5 Nf5 54.Rh1 winning position (C) 49...Ne7 50.Rb1 Ra3 51.f4 Kc5 52.Kf3 Ng6 53.f3 Nh4+ 54.Kg4 Ra4+ 55.Kh5 winning position I have not been able to find a save for Black.
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However, I believe Black still has a draw after 38...Rxa2 39.Rh6 Rc2 40.g4 a3 41.h5 Rc5 42.Bf7 Ra5 43.Ba2 Rb5 44.Bb3 Ra5 45.Re6 a2 46.Bxa2 Rxa2 47.h6 (I agree with <Pawn and Two> that this may be the key line) 47...b3! (not 47...Ra8?) 48.Re1 b2 <White to move: a draw?>
click for larger view(A) 49.Rb1 Ne5 50.g5 Ng6 51.Kg3 Ka5 52.f4 Kd4 53.f5 Ra5 59.Rxb2 Rxf5 = (B) 49.h7 Ra8 50.g5 Rh8 51.Rb1 Rxh7 52.Rxb2+ Kc5 53.f4 Rh4 54.Kg3 Rh1 and this seems to be a draw: 55.f5 Rg1+ 56.Kh4 Rh1+ 57.Kg4 Rg1+ 58.Kh5 Rf1
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and if 59.Kg6 then 59...Ne7+ wins the f-pawn; or 59.f6 Ne5 holds. |
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| Jul-14-09 |
| CharlesSullivan: <Pawn and Two> also suggested 38...Rxa2 39.Rh8 b3 and now (A) 40.g4 seems to lead to approximate equality: 40...Ra1 41.Bxc6 Kxc6 42.Rb8 Rb1 43.Ra8 and now perhaps 43...b2 (even more drawish is 43...Rd1) 44.Rxa4 Kb5 45.Ra8 Rg1+ 46.Kxg1 b1=Q+ 47.Kg2 Qxd3 and Black should not lose (B) 40.h5 Rc2 41.h6 Rc5 and now, instead of going into the main line with 42. Bf3, White can try 42.Bf7, but this leads to equality; here is a sample line from Rybka3: 42...b2 43.Ba2 Rh5 44.Bb1 a3 45.g4 a2 46.Bxg2 Ra5 47.Bb1 Ra1 48.h7 Rxb1 49.Rb8+ Nxb8 50.h8=Q Rg1+ 51.Kxg1 b1=Q+ 52.Kg2 Nc6 53.f4 Qxd3 = |
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Jul-18-09
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| Pawn and Two: <CharlesSullivan> In the line, 38...Rxa2 39.Rh6 Rc2 40.g4 a3 41.h5 Rc5 42.Bf7 Ra5 43.Ba2 Rb5 44.Bb3 Ra5 45.Re6 a2 46.Bxa2 Rxa2 47.h6 Ra8 48.g5 b3, you have indicated White can win with 49.Re1!. After 49.Re1!, the best line appears to be 49...Rh8 50.Kg3 Kc5 51.f4 Kb4 52.Kg4 b2 53.Kh5. At this point, Fritz indicated that 53...Kc3 was a better try for Black than 53...Nd4. But even after 53...Kc3, Fritz found the win for White: 53...Kc3 54.g6 Ne7 55.Kg5 Nxg6 56.Kxg6 Rg8+ 57.Kh5, (2.19) (26 ply) 57...Rg2 58.h7 Rh2+ 59.Kg6 Rg2+ 60.Kh6 Rh2+ 61.Kg7, (3.58) (23 ply) 62...Rf2 63.Rh1 Rh2 64.Rb1 Kxd3 65.f5 Kc2 66.Rg1 b1Q 67.Rxb1 Kxb1 68.f6 Rf2 61.Kg7, and White has a clearly winning position. I will next review your drawing solution for this line, 47...b3, instead of 47...Ra8. |
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Jul-18-09
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| Pawn and Two: <CharlesSullivan> In the line, 38...Rxa2 39.Rh6 Rc2 40.g4 a3 41.h5 Rc5 42.Bf7 Ra5 43.Ba2 Rb5 44.Bb3 Ra5 45.Re6 a2 46.Bxa2 Rxa2 47.h6, your move 47...b3!, appears to allow Black to draw. After 47...b3! 48.Re1 b2 49.Rb1 Ne5 50.g5 Ng6 51.Kg3 Kc5 52.f4 Kd4 53.f5 Ra5 54.Rxb2 Rxf5, Fritz indicated this position was favorable for White, but after a few additional moves the position became equal: (1.80) (24 ply) 55.Kg4 Rf1 56.Rh2 Nf8 57.Rh3, (.86) (24 ply) 57...Rg1+ 58.Rg3 Rh1 59.Rf3 Ng6 60.Rf2 Ne7, (.33) (22 ply) 61.Ra2 Rg1+ 62.Kf4 Rf1+ 63.Kg3 Rg1+ 64.Rg2 Rxg2+ 65.Kxg2 Ng6, with an equal position. After 48.Re1 b2, Fritz preferred the continuation 47.h7 Ra8, (1.50) (22 ply) 50.Rb1 Rh8 51.Rxb2+ Kc7 52.f4 Rxh7 53.Rb3 Kd6 54.Ra3 Nd4, but after (.89) (22 ply) 56.Ra6+ Ke7 57.Ra4 Ne6 58.Ra7+ Kf6 59.Ra6 Ke7 60.f5 Nc5 61.Ra7+ Kd6 62.d4 Nb3. Black can then win the d-pawn in a few more moves, and the resulting position appears to be a draw. So far our explorations indicate Black can obtain a draw in the variations beginning with: 38...Rxa2 39.Rh6. I will do additional review for the following lines: 38...Rxa2 39.Rh8 b3 40.h5 Rc5 41.h6 Rc5 42.Bf7, and 38...Rxa2 39.Rh8 Rd2, and finally 38...Rxa2 39.Rh8 Rc2. The move 38...Rxa2! is certainly proving itself in providing Black with excellent drawing chances. |
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| Jul-19-09 |
| CharlesSullivan: <Pawn and Two> After 38...Rxa2 39.Rh6 Rc2 40.g4 a3 41.h5 Rc5 42.Bf7 Ra5 43.Ba2 Rb5 44.Bb3 Ra5 45.Re6 a2 46.Bxa2 Rxa2 we have already analyzed 47.h6 as a draw. Another try in this position is 47.g5, but Black still draws after 47...Ra5 48.f4 Ra2+ 49.Kg3 Ra1 50.h6 b3 51.h7 Rh1 52.Rh6 Rxh6 53.gxh6 b2 54.h8=Q b1=Q 55.Qf6 Qxd3+. For example: 56.Kh4 Qe4 57.Kg5 Qg2+ 58.Kh5 Qh3+ 59.Kg6 Qg4+ 60.Kh7 Qd7+ 61.Kh8 Qc8+ 62.Kg7 Qg4+
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and Black's queen is strong enough to hold the draw. |
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Jul-19-09
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| Pawn and Two: <CharlesSullivan> We have both reviewed the line: 38...Rxa2 39.Rh8 b3 40.h5 Rc2 41.h6 Rc5 42.Bf7. Your latest analysis shows this line leading to equality after: 42...b2 43.Ba2 Rh5 44.Bb1 a3 45.g4 a2 46.Bxa2 Ra5 47.Bb1 Ra1 48.h7 Rxb1 49.Rb8+ Nxb8 50.h8Q Rg1+ 51.Kxg1 b1Q+ 52.Kg2 Nc6 53.f4 Qxd3=. However, after 42...b2 43.Ba2 Rh5 44.Bb1 a3, White has a better continuation with: 45.h7 Kb7 46.g4 Rh4 47.d4 Rxg4+ 48.Kf3 Rh4 49.d5 Ne5+ 50.Kg3 Rh1 51.Kg2. After 51.Kg2, White is winning. A likely continuation would be: 51...Nf7 52.Kxh1 Nxh8 53.Kg2. This line is promising for White, but it may yet only yield a draw, as I expect you will find some improvements for Black. |
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| Jul-19-09 |
| James Demery: These 2 have such a similar playing style. I`m surprised all their games aren`t draws. |
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| Jul-19-09 |
| AnalyzeThis: Capa said after the game that the move that surprised him was not 17. Qc1, it was 16. Kg2. |
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| Jul-20-09 |
| CharlesSullivan: <Pawn and Two>: After 38...Rxa2 39.Rh8 b3 40.h5 Rc2 41.h6 Rc5 42.Bf7 b2 43.Ba2 Rh5 44.Bb1 a3 45.h7 Kb7 46.g4 Rh4 47.d4 Rxg4+ 48.Kf3 Rh4 49.d5 better than 49...Ne5+ is 49...Nb4 50.d6 a2 51.Bxa2 Nxa2 52.d7 b1=Q 53.Rb8+ Kxb8 54.d8=Q+ Ka7 55.Qxh4 Qd3+ <Black has perpetual check...>
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and the Black queen can check forever, it appears. For example, 56.Kg4 Qe4+ 57.Kg3 Qg6+ 58.Kf4 Qf7+ 59.Ke5 Qg7+ 60.Ke6 Qg6+ 61.Ke7 Qg7+ 62.Ke8 Qg6+ 63.Kf8 Qf5+ 64.Kg7 Qd7+! (not 64...Qe5+ 65.Qf6 Qc7+ 66.Qf7 wins) 65.Kg6 Qe8+! 66.Kf5 Qd7+ etc. Zappa Mexico II never has any problem identifying this line as a perpetual check, but it took quite a few variations and hours to "prove" to Rybka3 that the position in the diagram is a draw. But perhaps you will find another improvement? |
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Aug-03-09
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| Bridgeburner: It is obvious that <38...Rxa2> substantially diminishes White's winning chances, but it's a shock to see how close it could have come to setting up a win for Black...theoretically. No one will ever figure out a game continuation that occupies powerful computers for weeks on end with no result other than a vague suspicion it's possible. Against that is the knowledge that the defender has to find all the right moves as well, so the scope for further mistakes, especially very subtle ones, is overwhelming. |
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Aug-07-09
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| Pawn and Two: <CharlesSullivan> Sorry for the delay in my response. I was on vacation. After additional review Fritz agrees that after: 38...Rxa2 39.Rh8 b3 40.h5 Rc2 41.h6 Rc5 42.Bf7 b2 43.Ba2 Rh5 44.Bb1 a3 45.h7 Kb7 46.g4 Rh4 47.d4 Rg4+ 48.Kf3 Rh4 49.d5, Black would be able to draw by 49...Nb4. Our analysis has strongly indicated that 38...Rxa2 39.Rh8 b3 leads to a draw. My earlier analysis (see my post of July 6th) indicated Black also has good drawing chances with: 38...Rxa2 39.Rh8 Rd2, or 38...Rxa2 39.Rh8 Rc2. Perhaps someone will find a promising continuation for White after 38...Rxa2!, but at this point I believe 38...Rxa2! would have given Black a position he could have drawn. |
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| Aug-13-09 |
| CharlesSullivan: <Pawn and Two> Yes, I believe we have shown that 38...Rxa2 leads to a draw after, for instance, 39.Rh8 b3! etc. By the way, I have spent several days looking at, after 38...Rxa2 39.Rh8, Fritz's two "drawish" suggestions: 39...Rc2 and 39...Rd2. I will post some small part of that analysis in the next day or so, but I believe both lose. By the way, I believe that Rubinstein missed easy wins at moves 36 and 37. As far as I can tell, nobody has pointed this out. For example, in this position < White played 37.Rh5+, but stronger is 37.h5! >
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White has 37.h5 (passed pawns must be pushed!) 37...b3 38.axb3 a3 39.d4+ Kb6 (39...Nxd4 40.Ra6 is easy for White) 40.Bd5 Rc2 41.b4
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and Black can resign (41...a2 42.Bxa2 Rxa2 43.d5 etc.). White also could have advanced the h-pawn one move earlier: 36.h5! leads to a crushing position. |
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| Aug-14-09 |
| CharlesSullivan: <Pawn and Two> Here is my analysis of 38...Rxa2 39.Rh8 Rc2 (analysis of 39...Rd2 will follow shortly). The best move here is 40.g4
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and I cannot find a way to save the game for Black. Here are some variations: (A) 40...Kc7 41.h5 Kd6 42.Bxc6 Rxc6 43.h6 winning position (B) 40...Ne5 41.g5 Nxd3 42.Be4 Rxf2+ 43.Kg3 Re2 44.Rb8+ Ke5 45.Kf3 Rh2 46.Rc8+ Kb6 47.Bxd3 winning position (C) 40...b3 (the main line) 41.g5
(C1) 41...Nb4 42.Rb8+ Ka5 43.Bc4 Rxc4 44.dxc4 a3 45.g6 b2 46.g7 b1=Q 47.g8=Q Qe4+ 48.Kg3 Qe5+ 49.f4 Qe3+ 50.Kg4 Qe2+ 51.Kg5 Qg2+ 52.Kf6 Qc6+ 53.Ke5 and Black does not have a perpetual check; White wins with his extra material (C2) 41...Re2 42.g6 Re7 43.Rc8 Ne5 44.h5 b2 45.d4 Rb7 46.Be4 Ng4 47.Bb1 Ka5 48.Kf3 Nh6 49.Rh8 winning position (C3) 41...Rc5 42.Bf7 Ne7 43.g6! (43.Rb8+ only draws) 43...Nxg6 44.Bxg6 Ra5 45.Bf7 Kc7 46.h5 Rg5+ 47.Kh3 Rf5 48.Bc4 Rf4 49.h6 Rxc4 50.h7 Rc6 51.Rc8+ Kxc8 52.h8=Q+ Kb7 53.Qg7+ Kb6 54.Qd4+ Kb5 55.f4 Rh6+ 56.Kg3 Rg6+ 57.Kf3 Rb6 58.f5 winning position |
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| Aug-16-09 |
| CharlesSullivan: <Pawn and Two> Now we look at sample variations after 38...Rxa2! 39.Rh8 Rd2(?). Here 40.Ra8! wins: (A) 40...Na5 41.Rb8+ Kc5 42.Bf7 Nc6 43.h5 Ne5 44.d4+! Rxd4 45.Be8 Ng4 46.Rc8+ Kd6 47.Bxa4 Ke7 48.Rg8 Nh6 49.Rg6 Nf7 50.Rb6
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and White wins (+5.98) with 2 extra pawns.
(B) 40...a3 41.h5 Rxd3 42.Bxc6 Kxc6 43.h6 Rd7 44.g4 Kd5 45.g5 Rh7 46.Kg3 Ke6 47.Kg4 Kd6 48.f4
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and White's kingside pawns win (+6.31).
(C) Long but straightforward is 40...Ne5 41.Rxa4 Nxd3 42.Kf3 Ne1+ 43.Ke4 Re2+ 44.Kf5 Rxf2+ 45.Ke5 Kb5 46.Ra8 Nd3+ 47.Kd4 Nc1 48.Rc8 Rd2+ 49.Ke5 Nd3+ 50.Kd6 Nf2 51.Rb8+ Ka5 52.g4 Ne4+ 53.Ke5 Nc5 54.Bc6 Nd3+ 55.Ke4 Nc5+ 56.Ke3 Rd3+ 57.Ke2 Rc3 58.Rb5+ Ka6 59.Rxb4 Ka5 60.Rb5+ Ka6 61.Be8 Ne6 62.Rb4 Rc2+ 63.Kf3
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and White wins (+6.37).
It looks as if the only draw for Black after 38...Rxa2 39.Rh8 is 39...b3! (See previous postings.) |
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| Aug-16-09 |
| CharlesSullivan: <Pawn and Two> In the 38...Rxa2 39.Rh8 Rd2 40.Ra8 variation, I failed to address the main point of 39...Rd2, namely 40...Rxd3. The refutation is 41.Bxc6! Kxc6 42.Rxa4 and White has a forced win; for example: 42...Kc5 43.Ra8 43.Rd7 44.Rc8+ Kd5 45.Rb8 Kc4 46.h5 Rh7 47.g4 b3 48.Kg3 Kc3 44.f3 b2 50.Rxb2 Kxb2
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and, according to the endgame databases, it is mate-in-26 beginning 51.Kh4! |
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Aug-17-09
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| Pawn and Two: <CharlesSullivan> 38...Rxa2 is slowly showing us its' secrets. In the line, 38...Rxa2 39.Rh8 Rc2 40.g4 b3 41.g5, Fritz calculated that 41...Kc5 42.Bxc6 b2 43.Bxa4 Rxf2+ 44.Kxf2 b1Q, may save the draw for Black. However, Fritz overlooked, 43.Rb8! a3 44.g6! a2 45.g7 b1Q 46.g8Q, and White is winning. In the other line, 38...Rxa2 39.Rh8 Rd2 40.Ra8, the winning ending you provided after 40...Rxd3 41.Bxc6! was amazing! In this line, you also indicated the following continuation: 38...Rxa2 39.Rh8 Rd2 40.Ra8 Na5 41.Rb8+ Kc5 42.Bf7 Nc6, as winning for White. Instead of 42...Nc6, Fritz prefers 42...Rxd3, with White continuing by 43.h5 Rd6 44.Ra8 Kb6 45.g4 Rf6, or 43.Ra8 Kb6 44.h5 Rd6 45.g4 Rf6. So far, I have been unable to prove a win for White after 42...Rxd3. What are your conclusions regarding this move? If a win for White cannot be proved after 42...Rxd3, then perhaps 41.Bf7 or 41.h5 should be considered. Also, 42.h5 may be stronger than 42.Bf7. I have only briefly reviewed these possibilities. |
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| Aug-18-09 |
| CharlesSullivan: <Pawn and Two> After 38...Rxa2 39.Rh8 Rd2 40.Ra8 Na5 41.Rb8+ Kc5 42.Bf7 Rxd3
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43.Be8 will win. For example, 43...a3 44.Rb5+ wins Black's knight and White has plenty of extra material to stop the queenside pawns. Or, 43...Nc6 44.Bxc6 wins--perhaps 44...a3 45.Rb5+ and (a) 45...Kxc6 46.Rxb4 wins with two extra pawns or (b) 45...Kc4 46.Ra5 Kb3 47.h5 etc. I'm quite surprised that Fritz seems to be struggling with these positions -- the analysis you post always is impeccable. Perhaps you are using only a small subset (or none?) of the available endgame tablebases? Of course, I could be overlooking something significant: I'm pretty much dependent on Zappa and Rybka, and they're certainly not infallible. |
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Aug-18-09
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| Pawn and Two: <CharlesSullivan> As you surmise, I am working without an endgame tablebase. When I upgrade my Fritz, I have to consider including an endgame tablebase. It took Fritz a while (32 ply!), to see that the ending after 42...Rxd3 was clearly winning. The position after 42...Rxd3 43.Be8 Nc6 44.Bxc6 a3 45.Rb5+ Kxc6 46.Rxb4, is very interesting. Black's passed pawn will eventully cost White his rook, but the combined White passers will win the game. I am pleased with our findings for this endgame. Perhaps someone will still discover a promising continuation for White after 38...Rxa2!, but we have provided strong evidence that this move would have allowed Black to draw. |
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| Aug-18-09 |
| CharlesSullivan: <Pawn and Two> Yes, the endgame tablebases are a "must." I, too, am satisfied that we have come pretty close to the truth of this position. I plan to send some notes to John Donaldson (of "The Life and Games of Akiva Rubinstein" fame). One last variation: after 38...Rxa2 39.Rh8 Rd2 40.Ra8 Rxd3 41.Bxc6 Kxc6 42.Rxa4 Kb5 43.Ra8 Rd5 44.g4 Rd4 45.Rg8 b3 46.h5 Kc6 47.h6 b2 48.Rb8 Rxg4+ 49.Kf3 Rh4 50.Rxb2 Rxh6
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Black is only one pawn down, but 51.Rd2 (the only winning move) cuts off the Black king and is mate-in-61. |
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| Sep-05-09 |
| WhiteRook48: 42 Bxb3 a1=Q and  but only slightly |
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