Shakmaty Bereolos - The Official Chess Site of Peter Bereolos

2/27/05 - Martinovsky-Bereolos, 1995 US Amateur Team Championship, Midwest

I noticed some new 6-piece with pawns tablebases on the Crafty FTP site this month. I've been looking at my games to see if these reveal any new discoveries. So far, there hasn't been much, but I guess that isn't too surprising. The most common 6-piece with pawn endings are ones where each side has a pawn (which are generally easy to assess as equal) or where one side has a two pawn advantage (which are generally easy to assess as wins for the stronger side). However, many exceptions exist.

My game against Eugene Martinovsky in the 1995 US Amateur Team Championship, Midwest reached a bishop plus two pawns vs. knight ending after 77... Nxf4+

This ending is won for White according to the tablebase, but it does hold some traps. The obvious problem is his bishop is on the wrong color to work with his h-pawn, so if Black can manage to sacrifice his knight for the f-pawn, then he will draw. Unfortunately for Black, his knight is on a terrible square to try to accomplish this. White's plan should be to keep the knight out of the action when the Black king cannot stop the two pawns on its own. 78. Ke5 Nh3 79. f6+ Kh6 80. Ke6 Ng5+ 81. Ke7 Kh7 82. Be4+ Kh8 83. h6? This is a mistake because of the second trick Black has, a fortress based on stalemate in the corner. The correct way is to squeeze the Black knight out of play 83. Bg6 Kg8 84. h6 Kh8 85. Kd6 Kg8 86. Ke5 Kh8 87. Kf5 Nf3 88. Kf4 Nd4 (88... Nh4 89. Bf5 Kg8 90. h7+ Kh8 91. f7!) 89. Bf5 Kg8 90. h7+ Kh8 91. f7! +- 83... Kg8? Black needs to use the stalemate trick to force White to overextend the h-pawn. 83... Nf7! = 84. h7 Ne5 with the idea Ng6-f8 as in the game 84. Bg6 Kh8 85. Kd6 Kg8 86. Ke5 Kh8 87. Kf4 87. Kf5 not allowing the knight to come back to the defense, seems simpler. 87... Ne6+ 88. Ke5 Nf8 89. Bf5 Kg8 90. h7+? Now Black holds the draw. White could still win with 90. Kf4, there are still stalemate tricks but the pawn being on h6 to deprive Black of the resource Kg7 makes all the difference as can be seen in the line 90...Kf7 (90... Kh8 91. f7) 91. Kg5 Kg8 92. Bg6 Kh8 (92... Ne6+ 93. Kg4 Nf8 94. f7+ Kh8 95. Bf5 is similar) 93. Kh5 Ne6 94. Kg4 Nf8 95. Bf5 Kg8 96. Kg5 Kh8 (96... Kf7 97. h7) 97. f7 Ng6 98. Kf6 Nf8 99. Ke7 Ng6+ 100. Ke8 Nf8 101. Bg4 Ng6 102. Bh5 and wins 90... Kh8! 91. Kd6 Ng6! 92. f7 Nf8! 93. Ke7 Kg7! 94. Be4 Kh8! 95. Bc6 Nxh7! 96. Be4 Nf8! 97. Bd3 [½:½] Black is holding with 97... Kg7!

This analysis has made me rethink my assessment of the B+3P vs. N+P ending as drawn. Martinovsky found an excellent plan to break down my first fortress, culminating in 68. Kh4 forcing Black to move his d-pawn. After White collects the d-pawn, if Black tries to sit on the Kf6/Nh6 fortress, White can just return with Kh4 (or make the end around ending with Kh7). The plan chosen in the game with Nxf4 does not seem to work, so I am not sure how else Black can hold.

2/25/05 - A Mysterious Endgame

I was recently looking at the first chapter of Jacob Aagaard's book Excelling at Technical Chess. This chapter was basically an introduction and he used the rook ending from the game Timman-Karpov from the 1988 Belfort World Cup. The points Aagaard was looking to make were finished at move 52, which he concluded was basically a won position for Black. He gave the rest of the moves without comment. In playing over this latter stage, I uncovered some strange happenings near the end of the game. Everything is fine through White's 69. Kh1

The conclusion in Aagaard's book is 69...Rg4? 70. Kh2? did both players really miss the stalemate trick 70. Rxh3+! 70... Rg2+ 71. Kh1 Rg3 72. Rc4+ Rg4 73. Rc3 Rb4 74. Ra3 Rg4? 75. Rc3? 75. Rxh3+! 75... Kg5 76. Kh2 Rh4 [0:1] It seemed very fishy to me that two world class players would miss such a tactic not once, but twice, so I started checking other sources. Chess Assistant and Chess Lab both have the conclusion as above. Chess Base has a slightly different version, leaving out a couple of moves 69... Rg3 70. Rc4+ Rg4 71. Rc3 Rb4 72. Ra3 Rg4? 73. Rc3? (73. Rxh3+) 73... Kg5 74. Kh2 Rh4 So again, the missed stalemate trick, but this time only once. Finally, I found a third version at that concluded simply 69...Rg3 0-1 At least this avoids the stalemate trick, but I would think that having played it out this far, Timman would have at least gone for 70. Rc4+ Rg4 71. Rc3 in order to make Black demonstrate the Kg5 idea.

The only other source I had was Inside Chess Vol. 1, Issue 15. The moves are not given, but there is the comment, "Timman lasted only a few moves when the adjournment was resumed". Hard to figure out what a few means. I would guess they adjourned somewhere around move 60. If anyone else can shed further light on this mystery, I would be glad to hear from you.

2/22/05 - Pawn Endings at the US Championship

This will be the first post in what will hopefully be a series of posts on endgames at the US Championship. I'll start with the most basic endgame, the pawn ending. Actually, the pawn endings weren't very interesting, but for completeness sake, I'll analyze them here. I already covered the ending Casella-Zenyuk, which illustrated Bahr's rule. Another illustration of Bahr's rule, this time with the defender able to hold the draw, occurred in the 1st round game between IM Levon Altounian and Esther Epstein after 55. fxe6

55...Kxe6 56. Kh5 White is going to capture the h-pawn and Black is obviously too slow if she tries to run after White's a-pawn, so we reach a Bahr's rule position with opposed rook pawns and an extra outside passed pawn. With the pawns opposed on a4/a5 Bahr's Rule states that the position is drawn if the White pawn has not crossed the h2-b8 diagonal. However, rather than memorize a rule it is better to understand what is going on. White will decoy with the outside passed pawn, the Black king will have to capture it and then hope to get back in time to c7 or c8 in order to save the draw. Obviously the further up the board the Black king has to travel, the longer it takes to get back which is why it is preferable to have the pawn on h2 rather than h4. Like wise on the other side of the board, the position of the a-pawns determines how much work the White king will have to do in order to shoulder off the Black king from reaching c7. So Black prefers the pawns to be locked on a2/a3 and White on a6/a7. This explains Black's next move, even though it is not immediately necessary 56... a5 The point about the queenside pawn structure is illustrated by the variation 56... Kf6 57. Kxh6 Kf5 58. a4 Kf6? (58...a5! still draws) 59. a5! Kf5 60. Kh5 Kf6 61. Kg4 Kg6 62. Kf4 Kh5 63. Ke5 Kxh4 64. Kd6 Kg5 65. Kc6 Kf6 66. Kb6 Ke7 67. Kxa6! Kd7 68. Kb7! and the Black king fails to reach c7 or c8. 57. Kxh6 Kf6 While Black would prefer the pawn structure a3/a4 on the queenside, there is still the matter of actually capturing the White h-pawn, so not 57...a4? 58. Kg7 and the h-pawn will queen. 58. a4 Kf5 59. Kh5 Kf6 60. Kg4 Kg6 61. Kf4 Kh5 62. Ke5 Kxh4 63. Kd5 Kg5 64. Kc6 Kf6 65. Kb6 Ke7 66. Kxa5 Kd7 [½:½]

The other pawn endings in the championship were pretty straightforward, so I'll just show them quickly. In the 6th round Tennessee's Jake Kleiman, showed the power of the outside passed pawn against Vanessa West after 58. exf6

Black will capture the f-pawn to restore material equality, but White has the simple plan of using the passed d-pawn as a decoy to open the way for his king to capture the remaining Black pawns. 58...Kg6 59. Kf3 Kxf6 60. Kf4 Ke6 61. Ke4 Kd6 62. Kf5 Kd5 63. Kf6 Kxd4 64. Kxf7 Ke4 65. Kg6 Kf3 66. Kxh6! One last trap would be to capture the wrong pawn first with 66. Kxh5? Kxg3! = [1:0]

Grandmasters Larry Christiansen and Walter Browne had a pawn race in their 2nd round game after 41...Kxd6

42. Kf4 Kd5 43. Kf5 Kc4 44. Kf6 Kb3 45. f4 Kxa3 46. f5 a4 47. Kxf7 Kb3 and here the draw was agreed in light of 48. f6 a3 49. Kg8 a2 50. f7 a1=Q 51. f8=Q. Actually I'm not sure why they chose this point to sign the peace treaty, since the diagramed position was just after the time control, they could have split the point then, or played a few extra moves here to get down to bare kings. [½:½]

In the 8th round, the point was split immediately after the time control in the locked position between GMs Varuzhan Akobian and Julio Becerra after 40...cxb6

41. Ke3 [½:½] The only useful pawn break is after 41...Ke6 42. Kf3 f5 and then the position becomes totally blocked after 43. gxf5+ Kxf5 44. g4+

2/16/05 - Basic Chess Endings, Revised Edition

They had the new BCE at the public library, so I checked it out. I was a bit disappointed. There were some positives. The layout is much improved, with algebraic notation and individual numbering for each position. Also, the verbal discussion in the notes is still high quality and makes this edition (as well as the old one) worthwhile.

Since the numbering is different and positions have been added and deleted, it is not completely clear how much effort went into correcting the analysis from the Fine edition. Here is an example I found of one they missed. In the Benko edition it is Position #67 titled Black to play, White wins. This is Position #41 in the Fine edition

After 1...Kf4! 2. Ke2 Ke4! 3. g3 the tablebases will show you that Black draws with 3...Kf5! instead of Fine's 3...g5? In this day and age it is completely unacceptable to publish an endgame encyclopedia with an error in a 5-piece ending. I'm sure that some of the newer 6-piece endings on the Crafty FTP site will uncover further analytical improvements.

There is no Bibliography, so I presume that other analyses that have revisited some of the positions were not consulted. Here's are a couple of examples. First, the classic from the game Capablanca-Tartakower, New York 1924. (Position #404) in the Fine edition, (#818 in the Benko edition)

The analysis in the Benko edition is the same as in the Fine edition. Dvoretsky's Endgame Manual gives some other resources for Black after 1. Kg3 Rxc3+ 2. Kh4 and Dvoretsky gave further analysis of this ending in his ChessCafe column. Strangely, some of this discussion was also covered in Benko's Chess Life column, but didn't make it's way into the book.

Another example is position #237f in the Fine addition, which is unchanged as #500 in the Benko edition.

GM Shipov analyzed the above position on the old Club Kasparov website, finding numerous errors in Fine's analysis and also in the related position after 1. Be4 g6 2. Bd5 which is Fine's #237e and Benko's #499 (these should have been consolidated as Shipov did).

These examples seem to indicate that the revision was somewhat of a half-hearted, or perhaps rushed effort. I think this is an injustice to the legions of players who have gone through the Fine edition with a fine-toothed comb over the years. In the introduction to Batsford Chess Endings, Speelman states that book was 10 years in the making, and I think that is the sort of labor of love most people were looking for in the revision of Basic Chess Endings. Since Benko's Chess Life column is still top-notch and his autobiography deservedly won the ChessCafe Book of the Year award, it isn't clear to me why this wasn't the case.

Because of all of this, I'll continue to maintain my BCE corrections page. I've rewritten the introductory page and will start to put updates on the individual pages showing the changes, if any, between the Fine and Benko editions.

2/8/05 - Land of the Sky

The annual Land of the Sky tournament was held the weekend before last in Asheville, North Carolina. The threat of bad weather and remodeling at the hotel conspired to keep attendance way down. Still, the open section was very strong with 5 GMs and a couple of IMs. I played better than I did in Clarksville, but some bad luck and missed opportunities left me with an even score.

For a change, I decided to play the Friday evening round. Doug Hyatt ended his tournament hiatus and drove up with me, and we got paired together in the first round. I had White in a maneuvering game, where I had a slight edge because of a bit more space and the bishop pair. After 27...Rdc8?!

Now, instead of my 28. h4 28. c5 threatening both Ba6 and cxd6, dissolves my only weakness and seems to leave white with a very comfortable game. After the text he was able to correct things with 28... Rc7 and white only has the small plus he initially had. I played the time pressure phase pretty poorly and ended up scrambling to a draw in the ending.

In the second round I had Black against John Curcuru. He played an unsound exchange sacrifice in the ending, overestimating his connected passed pawns. After 31. f7

his pawn is overextended and his knight is tied to its defense. Short of time (but he was even shorter), I played to activate my rook with 31... Ke7 Instead, 31... Rd8 gives Black all the winning chances. The bad part of it was despite his time pressure, all of his moves are practically forced, so it should have been simple to calculate the variation that occurs in the game. 32. e5 Rd2? I could correct my mistake with 32... Rd8 33. e6 Re2 Now, 33... Rd8 34. Ke5 isn't at all bad for White. It looks as though Black is winning, but when his king and rook take the White pawns, they end up on unfortunate squares and get forked. 34. Ng8+ Kf8 35. Nf6 Rxe6 36. Nxh7+ Kxf7 37. Ng5+ Kf6 38. Nxe6 Kxe6 39. Kg5 Kf7 40. c4 [1:0]

In the 3rd round I had White against Chris Mabe. I got a wretched position out of the opening, a pawn down with no compensation after 18. a3

He went for a tactical trick with 18...Nc6?! Instead 18... Na6 leaves White struggling. I was now able to restore material equality with 19. dxc6! Qxd1+ 20. Kxd1 Nf2+ 21. Kc2 Nxh1 22. Be3 taking away the knight's retreat to f2 22... Rh5 23. Nf4 Ng3 23... Rh6 24. Nd5 24. Nxh5 Nxh5 25. cxb7 Rb8 and I ended up winning the ending after 26. Bxc5 but 26. Rd1 may be even better.

The next morning, I had a pretty smooth victory over Jeffrey Kidd with the Black pieces. I already had a comfortable game after 18... Kh7 preparing to drive his pieces back starting with ...g6.

I thought he might go for a piece sacrifice instead of getting pushed back, but it didn't seem like he had enough pieces in the attack for this to be dangerous. He did go for the sacrifice via 19. f4 exf4 20. Bxf4 Nh5 21. Rg4 Nxf4 22. Rxf4 g5 but his attack was too slow after 23. Rf2 gxh4 24. Raf1 Qg5 25. Rf4 Rad8 26. Rg4 Qd2 and Black is already counterattacking and won shortly

In the final round I had Black against IM Renier Gonzalez. A win would vault me up into 3rd place. I was a bit uncomfortable out of the opening, but had a chance to come very close to equalizing after 19. Rae1

White's advantage is mostly based on the superiority of his minor pieces, but here I could eliminate both sets of minor pieces with the combination 19... Bxh3 20. Bxh3 Qxd5 21. Bg2 Qf7 22. Bxc6 bxc6 23. Qxc6 when the slight weakness in Black's pawn structure leaves White with only a minimal advantage. Instead I prepared an exchange of queens on g7 with 19...Rac8 and eventually lost a long endgame.