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Up Topic Rybka Support & Discussion / Rybka Discussion / Latests versions of Rybka : improvement for training
- - By sylvain.renard.27 (**) Date 2007-07-23 09:56
let's suppose you want to improve your chess skills and set some positions on the screen (or better on a DGT board to be in more realistic conditions of play).
You set the chess program on a game mode (for instance 5 minutes / game) not analysis mode.

8/1R1k1p1b/3p2rP/2pP4/2P2rp1/2P2pP1/8/5RK1 b - -

You just played 1.Rb7+
With Rybka 1.2f, you will have a very bad surprise : 1...Kd8 2.Ra1 Rxc4?? 3.Ra8 checkmate

Let's try again with Rybka 2.3.2.a 32 bit : 1...Kd8 2.Ra1 Kc8 3.Rab1 f2+ 4.Kf1 Kd8 5.Ra7 Kc8 6.Ra8+ Kc7 7.Rab8 Rd4 8.R1b7 checkmate

When you are training at chess, you hope that your opponent plays the hardest move for your side. Of course, for Rybka, -#8 (or in more moves...) is obvious, but it is not for the human player! The worse would be for an engine :  -#28, oh I resign! Human player : mate in 28? where??? :)

Thank you for this improvement!
I already talked about this problem many months ago, and the strangest thing (for me) was that in analysis mode, Rybka 1.2f was not showing 2...Rxc4 but was only playing it in a real game. She had "suicidal tendances" ? :) (a comment Amir Ban did about my program "Capture" in Paris 1997, when it played a dubious move against Junior... At that time, I did not appreciate very much his sense of humor :( ...)
  Best regards,
Parent - - By Vasik Rajlich (Silver) Date 2007-07-24 06:39
I know what you mean, but hardest and easiest are subjective.

I do have some ideas for 'human-like' play. One is to semi-randomly throw moves out of the search tree for both colors. This is actually not that far from what humans do when they play chess.

Parent - - By sylvain.renard.27 (**) Date 2007-07-24 08:54
In the example I gave there was a forced mate in 8 moves. Rybka 1.2f transformed it in a mate in 3 moves, it was not subjective. So the human player who was training (me) was frustrated! The engine should never shorten the mate. In more complex positions (or in difficult endgames) the human player will not necessarily see a long term win or mate. Of course in other positions, it might not be easy to determin which is the best defensive move in a theorically lost position.
Rybka 1.2f was doing hara-kiri by playing 3.Rxc4??. It looked like her reaction was : "Oh I will lose anyway, so let's lose quickly...". I'm glad you gave her anti-depressor medecine to avoid this type of behavior :).
  Best regards,
Parent - By h1a8 (***) Date 2007-07-24 11:38
Ha Ha Ha. You have a good sense of humour.
Parent - By Vasik Rajlich (Silver) Date 2007-07-26 07:38
Aha, I understand. Newer Rybka versions are better about this, although I'm not sure that they're perfect.

Up Topic Rybka Support & Discussion / Rybka Discussion / Latests versions of Rybka : improvement for training

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