Author: Marc Bourzutschky
Date: 15:45:36 10/08/02
The Chessmaster FEG program (downloadable from www.chessmaster.com) is a very
clever tool that allows the generation of 6-man EGDB's with pawns on a 32 bit
machine with limited resource requirements. This would not be possible with
the Nalimov program without some code changes. I have generated KRPPKR which
occurs relatively frequently in practice (next I'll generate KRPKRP and KRKPPP.)
Below some positions that are misanalyzed in ECE, and also give Fritz trouble
even when using 5-man tablebases. Unfortunately the file format of the FEG
tablebases is not public, so no automated search for mutual zugzwang
positions nor a systematic comparison with Nalimov's results is yet possible.
The position below is from ECE II, 468 and has some subtle zuzwang play:
[D] 4r3/8/5K2/2Pk4/3P1R2/8/8/8 b
[White "?"]
[Black "?"]
[Fen "4r3/8/5K2/2Pk4/3P1R2/8/8/8 b - - 0 1"]
[Result "1-0"]
1... Rf8+ 2. Kg5 Rg8+ 3. Kh5 Rg7 4. Rg4 Rf7 5. Kg6 Rf8 6. Kh6 ({ECE has only}
6. Rh4 Rf1 7. Kg5 Rf8 8. Rf4 Rg8+ 9. Kh5 Rg7 {and claims a draw}) 6... Rf1
7. Kg5 Ke6 8. Re4+ Kd5 9. Rf4 Rd1 10. Kf6 Re1 11. Kf7 Re2 12. Kf8 Re6 13. Rh4
Re1 14. Rh7 Re6 15. Rd7+ Kc6 16. Rd8 Rh6 17. Kg7 Rh5 18. Rd6+ Kc7 19. d5 Rg5+
20. Kf6 Rh5 21. Kf7 Rg5 22. Ke6 Rg6+ 23. Ke7 Rg7+ 24. Kf6 Rh7 25. Rc6+ Kd7
26. Re6 Rh6+ 27. Ke5 Rh5+ 28. Kd4 1-0
The position below could have arisen in Blackburne-Lasker (ECE II, 533):
[D] 8/8/7k/6pp/2R5/1r6/6K1/8 w
[Event "St Petersburg"]
[Date "1914.??.??"]
[White "Blackburne"]
[Black "Lasker*"]
[Result "0-1"]
[FEN "8/8/7k/6pp/2R5/1r6/6K1/8 w - - 0 1"]
1. Rc6+ Kg7 2. Rc5 Kf6 3. Rc6+ Ke7 ({After} 3... Ke5 4. Rc5+ Kf4 5. Rc4+ Ke3
6. Rc5 {
Black has to retrace his steps. ECE therefore considers the position drawn.})
4. Rc5 Rb2+ 5. Kf3 g4+ 6. Kf4 Rf2+ 7. Kg5 (7. Kg3 Rf3+ 8. Kg2 h4 9. Rg5 h3+
10. Kh2 Rf2+ 11. Kg1 Rf4 12. Kh2 Kf6 13. Rg8 Kf5 {also loses}) 7... Rh2 8. Kf4
Rh3 9. Rc6 g3 10. Kf3 h4 11. Kg2 Rh2+ 12. Kg1 Rf2 ({Fritz7 needs 25 ply to
avoid} 12... Kf7 13. Rh6 {with a draw}) 13. Rh6 Rf4 14. Kg2 Kf7 15. Kh3 Rg4
(15... Kg7 {also wins}) 16. Kg2 Kg7 17. Rh5 Kf6 18. Rh8 Rf4 19. Rf8+ Ke5
20. Re8+ Kd5 21. Rd8+ Ke6 22. Re8+ Kf7 23. Re2 Kf6 24. Kh3 Rd4 25. Ra2 Re4
26. Ra8 Re1 0-1
The following position by Minev (ECE II, 564) features an interesting stalemate
defence:
[D] 8/7k/7P/5PK1/8/8/6R1/2r5 w
[White "?"]
[Black "?"]
[Result "1/2-1/2"]
[FEN "8/7k/7P/5PK1/8/8/6R1/2r5 w - - 0 1"]
1. f6 Rc5+ 2. Kf4 Ra5 {Fritz7 has White ahead by 5.25 after 26 plies.} 3. f7
Ra4+ 4. Kf5 Ra5+ 5. Kg4 Ra4+ 6. Kh5 Rf4 7. Rg7+ Kh8 8. Kg5 (8. Rg8+ Kh7 9. f8=Q
Rxf8 10. Rxf8 {stalemate}) 8... Rf5+ {with repeated check or stalemate.}
1/2-1/2
The position below is by Kopayev (ECE II, 586). White can win, but not in the
manner given in ECE:
[D] 8/r7/8/5k1P/6R1/5PK1/8/8 b
[White "?"]
[Black "?"]
[Result "1-0"]
[FEN "8/r7/8/5k1P/6R1/5PK1/8/8 b - - 0 1"]
1... Kf6 2. h6 Rh7 3. Ra4 (3. Rh4 {only draws after} Kf7 4. Kg4 Kg8 5. Kh5
Ra7 6. Rg4+ Kh8 7. f4 Ra5+ ({ECE only considers} 7... Ra1 {which loses after
} 8. f5 Kh7 9. Rg7+ Kh8 10. Rg4 Kh7 11. f6 Rh1+ 12. Kg5 Rxh6 13. f7 ) 8. Rg5
Ra1 9. f5 (9. Rb5 Rh1+ 10. Kg6 Rg1+ 11. Rg5 Rh1 12. Ra5 Rg1+ 13. Kf6 Kh7 {=})
9... Rh1+ 10. Kg6 Rxh6+ {=}) 3... Kg6 4. Ra6+ Kh5 5. Rb6 (5. Ra1 {!?} Kg6
6. Rh1 {?} Kf7 {!} {With the same draw as after 3.Rh4?}) 5... Kg5 (5... Ra7
6. f4 Ra3+ 7. Kf2 Kg4 8. Rf6 Rh3 9. Ke2 Rh1 10. Ke3 Re1+ 11. Kd4 Re7 12. Kd5
Kh5 13. Kd6 Rh7 14. f5 Kg5 15. Ke6 Ra7 16. Rg6+ Kh5 17. Kf6 Ra6+ 18. Kg7 Ra7+
19. Kh8 {+-}) 6. f4+ Kf5 7. Rb5+ Kg6 8. Kg4 Ra7 9. Rb6+ Kh7 10. Kg5 Ra1
(10... Rc7 11. Re6 Ra7 12. f5 {+-}) 11. Rb7+ Kg8 12. f5 Rg1+ 13. Kf6 Ra1
14. Re7 Ra2 15. Ke5 Re2+ 16. Kd6 Rd2+ 17. Ke6 Re2+ 18. Kd7 Rd2+ 19. Ke8 Rf2
20. Re5 Kh7 21. Kf7 Ra2 22. Re6 Ra8 23. Re8 1-0
The position below features interesting play with a bishop of the "wrong" color.
It is due to Minev and is misanalyzed in ECE III, 1196:
[D] 1r5k/R6P/6BK/8/8/8/8/8 w
[White "?"]
[Black "?"]
[Result "1-0"]
[FEN "1r5k/R6P/6BK/8/8/8/8/8 w - - 0 1"]
1. Ra1 Rd8 2. Bf5 {White's winning plan is to bring the bishop to the a2-g8
diagonal and threaten a deadly rook check on g8. At the same time White has to
ensure that he is left with a winning KRBKR ending if Black captures the pawn
on h7. Timman in ECE only gives 2.Bf7?, when Black can draw with 2... Rd6+ 3.
Kg5 Kxh7.} Rf8 3. Kg5 Re8 (3... Kg7 4. h8=Q+ {leads to a won KRBKR ending.})
4. Bh3 {In the sequel Black has several chances of capturing the h7 pawn,
which all lead to lost KRBKR endings.} Rd8 5. Be6 Rb8 6. Kg6 Rf8 7. Ra2 Rc8 8.
Kf7 Rb8 9. Ke7 Rb7+ 10. Kf6 Ra7 11. Rd2 Ra8 12. Rg2 1-0
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Last modified: Thu, 15 Apr 21 08:11:13 -0700
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