RYBKA Beta - GANDALF

15th IPCCC 2005 round 7

Caro Cann Defense B12

Topic: Tactical transformation of material advantage in the endgame

IM Marek Matlak

1.e4 c6 2.d4 d5 3.e5 Bf5 4.Bd3 Peaceful move, sure Rybka had it in her opening book. More chances for advantage promises white 4.Nf3, 4.Nc3, 4. Be3 or 4.h4. 4...B:d3 5.Q:d3 e6 6.Nf3 Nd7 For the moment Gandalf prefers also peaceful play. More aggressive way was to continue with 6...c5 with the idea 7…Nc6 7.Nc3 Human would probably consider castling first - it leaves a question where to put the knight open. 7...Ne7 8.0–0 Nf5

WHITE TO MOVE

9.a4!?N In this position white usually played 9.Ne2 or 9.Bf4. The game Korneeev O.- Gomez Esteban J. (1999) continued this way: 9.Ne2 Be7 10. c3 h5 11.Ng3 g6 12.Re1 h4 13. Nf1 c5 with equal chances. Rybka’s move 9.a4!? has its point - it will take away b6 square from black pieces. If black would play a5 itself, then black would be have to forgot about his main counterplay plan with c6-c5, because b5 square then would be too weak. 9...Be7 10.g4! Looks like Little Fish has eyes around the board J Now it is time for some action on the kingside. 10...Nh4 11.N:h4 B:h4

WHITE TO MOVE

12.f4 The threat is not only f4-f5, black has to consider also g4-g5. 12...Be7 13.f5 c5? Too optimistic. Here is why: first - black king is still on the center, second - blacks development is worst than whites and therefore black should not open a position, third - psychological mistake J one should not play tactic with Rybka... It was better to play 13. Bg5. 14.f:e6 f:e6 15.Nb5! White treats 16.Bg5 15...c:d4 [15...a6 16.Nd6+ B:d6 17.e:d6±]

WHITE TO MOVE

16.Bg5!! N:e5 Of course after:16...B:g5?? would be 17.Nd6+ Ke7 18.Rf7 mate. 17.Qg3 Bf6 18.Rae1! Rybka is developing exemplary attack 18...0–0 Black king manage to get out from center, but there must be a prize to pay…

WHITE TO MOVE

19.Q:e5!! Human describe such moves as "bolt from the blue", for comp is only few ply search. 19...B:e5! The best chances to rescue the game black has in the endgame. Hopeless was to play: 19...B:g5 20.R:f8+ K:f8 21.Rf1+ Kg8 (21...Bf6 22.g5+-; 21...Ke8 22.Nc7++-) 22.Q:e6+ Kh8 23.Nd6+- 20.B:d8 R:f1+ 21.K:f1 B:h2

WHITE TO MOVE

Tactical storm has stopped. Black for a time being has 3 pawns for a piece. However endgames are not strong side of computers play, Rybka carry out her material advantage pretty precisely. It is worth to mention, that the endgame has more tactical than technical character. 22.Be7 Kf7 23.Bd6! B:d6 24.N:d6+ Ke7 If 24...Kf6 then 25.g5+! K:g5 (25...Ke7 26.Nf5+ with similar position like in the game, only white has pawn on g5 instead on g4) 26.R:e6 White is winning, but it will take a lot of moves. 25.Nf5+ Kf6 After 25...Kd7 26.N:g7 White is winning but it requires still a lot of good moves.

WHITE TO MOVE

26.N:d4 White finally got a pawn. For a time being White has a passive king and the only chance for Black for a draw is to reduce pawns and get a rook versus rook and knight type of endgame. Rybka of course is not letting Gandalf to do it. ( IR: The author of Rybka Vasik Rajlich was curious and little worry the endgame rook & rook and knight no pawns may arise, cause he did not put this kind of draw endgame knowledge into his Beta version). 26...Re8 27.Kg2 e5 28.Rf1+ Human would play rather 28.Kg3! to avoid pawns exchanges. 28...Kg5 29.Nf3+ K:g4 30.Nh2+ Kh4 31.Rf7

BLACK TO MOVE

31…e4 Gandalf has still looked for counterplay 32.R:g7 h5 33.Nf1 d4 34.Nd2 a6?! More resistance was to play 34...Re5, but it would not affect game result anyway. 35.Nb3 Re5 36.N:d4 Rg5+ 37.R:g5 K:g5 Still one should be careful to not loose all pawns.

WHITE TO MOVE

How usually computers get help from tactics. 38.Ne6+! Kf5 39.Nc5+- Ke5 40.N:b7 Kd5 41.Kg3 Kc4 42.Nd6+ Kd5 43.Nf5 Kc4 44.b3+ Kd5 45.Kf4 e3 46.K:e3 Ke5 1–0