CCRL Discussion Board

In fact, any "leaper" chess piece with 4 moving paths can stalemate another piece of the same type. Leapers with 8 moving paths can escape each other. I am not sure if there is another terminology to describe the number of symmetrical moving paths a piece has, but I use "octosymmetri...

This was my position: (Kd1,Pb1/Kb4 12#). Sorry for the wrong coordinates. Great, yes, this is 12#! According to the database, there are 3 more wins in 12 in kpk. (Unique positions, not just reflections). Yes, the wK can be shifted to c1,d2, or d3 and after 1.Kc2 the result is the same as in (Kd1,Pb...

Yeah, of course KRK for pawnless, however maxDTM is only 7 moves. "Ka1,Rd4/Kc3" is one of those mates in 7: "3R/2k1/4/K3 w - - 0 1" 1.Ra4 Kb3 2.Ra2 Kc3 3.Ra3+ Kc2 4.Ka2 Kc1 5.Kb3 Kd2 6.Kb2 Kd1 7.Rd3# (If you find a hole, please tell me!). Correct! I played 5.Rc3 instead of 5.Kb3...

Can you guess the longest line length with 3 pieces, 4, 5, etc? (Also, which piece configuration has the longest line?) :-) 3 men pawnless tablebases: the KR/K endgame has the longest line. Maximum DTM probably 8. (Ka1,Rd4/Kc3) 3 men pawnful tablebases: the KP/K endgame has the longest line. (That ...

The author of the following study presumed that the RRN/RR 7 piece ending is a general draw... E.Vlasák (Hlinka JT, 2004) 8/8/kr6/8/1P3r2/4R3/3N4/3KR3 w - - 0 1 White wins 1. Ra3+ Kb7 2. Re7+ Kc6 3. Rc3+ Kd6 4. Rc4 Rxb4 5.Ree4! 8/8/3k4/8/1rR1Rr2/8/3N4/3K4 b - - 0 5 5... Rxc4 (5... Rxe4 6.Nxe4+ Kd5 7...

Following John's idea about key positions: maybe it is possible to create tablebases with a new metric: DTK - Depth to Key. These are some kind of compressed DTM tablebases where chess knowledge is also used. DTM is actually DTK where only the checkmate positions are considered as key positions. One...

DTM - Composers need this and nothing less. Study composers need less than DTM! We actually want the following informations about a position: 1.If it is a win/draw/lose (WDL). 2.In a drawn position: is the drawing move unique? 3.In a win position: is the winning move unique (except time losing move...

The longest DTM in the 5-piece pawnless endgames is DTM87. In the following position white needs 87 moves to checkmate the black King! The first 20 moves are unique, an alternative move appears only at move 21. http://www.polgarstarchess.com/M87ax.jpg Here are some analyses of one of the possible li...

There is also possible to have two e.p. captures in a mutual zugzwang position.

8/8/1p1p1p1p/1P1k1P1P/2p1p3/2P1P2P/2PPK3/8 w - - 0 1


Only 1.d4! (reciprocal zugzwang!) wins. White needs the extra tempo h3-h4 in some variations.

Position #405206 in the Sub-7-man DTM metric zugs pgn is wrongly listed as type A8.

I have modified this position (Z07) found here: http://centaur.reading.ac.uk/4518 8/8/8/2p5/1pP1p3/kP2P3/Pp1P4/1K6 b - c3 0 1 Now the following position is a chess study with only one winning move (1.c4!): 8/8/2p5/2p1p3/1p2p3/kP2P3/PpPP4/1K6 w - - 0 1 1.c4! (1.c3? c4! 2.cxb4 cxb3 3.axb3 Kxb3 -+) 1.....

The problem was that there were some composers who added a few moves (usually forced and with captures) to a position from the reciprocal zugzwang list and called that a "study". But AJR was wrong: there is nothing bad with a good EGTB study. I let you to discover the solution of the follo...

More compact format: 8/3b2KP/8/2R5/8/5R2/pk6/7r w - - acd 29/81; acn 62258191501; acs 432000; bm Ra5; c0 "Árpád Rusz - Sakkvilág, 2010"; ce 1355; pv Ra5 a1=N Rf2+ Kb1 Rf1+ Rxf1 Rxa1+ Kxa1 h8=Q Be6 Kh7+ Ka2 Qa8+ Kb3 Qb8+ Kc4 Qc7+ Kd5 Qa5+ Ke4 Qb4+ Kf3 Qf8+ Ke2 Qe8 Kd3 Qxe6 Rf4 Kg6 Kd4 Kg5 ...

7Q/6K1/4b3/8/8/8/8/k4r2 The question was: "Which is the only move by the white king that wins?" The answer: Only 7. Kh7!! is winning! 7...Ka2 8. Qa8+ Kb3 (8... Kb2 9. Qg2+ +-) 9. Qb8+! (9. Qb7+? Kc3 10. Qc6+ Bc4 =) 9... Kc4 (9... Kc3 10. Qe5+ +-) 10. Qc7+ Kd5 (10... Kd4 11. Qb6+ +-) 11. Q...

If you click the Quote button on the post with diagrams you can copy the FEN.

I propose a new topic about chess endgame studies composed with tablebase help. Árpád Rusz - Sakkvilág, 2010 8/3b2KP/8/2R5/8/5R2/pk6/7r White to move and win After 1.Ra5 a1Q 2.Rf2! Kb1 3.Ra1 Ka1 4.Rf1! Rf1 5.h8Q Be6 we get the following position: 7Q/6K1/4b3/8/8/8/8/k4r2 Try to guess which is the onl...

A nice problem composed with the help of the tablebases:

Do you already have automatic database verification? I don't have that yet. You are right, that is essential. The database looks correct but you never know what hidden small mistakes can be there... 80 DTM maximal depth positions for 5 men pawnless endgames: http://polgarstarchess.com/5%20Piece%20P...

Thank you!

I am at the very beginning of this work and I haven't optimized yet the solver. I am just happy that it seems to work. But optimization of the solver is the next step before I will start to generate the 6 men tablebases. I still have some bugs when I generate tablebases with pawns... That need to be...

I have build the tablebases in DTM format. Some interresting results (maximal length wins): http://polgarstarchess.com/M9x.jpg M9 http://polgarstarchess.com/M12x.jpg M12 http://polgarstarchess.com/M22x.jpg M22 http://polgarstarchess.com/M49x.jpg M49 (The bishop is much stonger than the rook!) http:/...

I have computed endgame tablebases up to 5 men for Starchess, a very interesting new chess variant played on a star-shaped board with 37 cells. See the rules here: http://polgarstarchess.com/Rules.doc http://polgarstarchess.com/Starting%20Position%20small%20board.jpg Probably most of you never heard...

I hope somebody has this tablebase...
White to move. It is a win or only a draw? Thanks!

2KN4/8/6b1/8/3Q4/5k1B/8/1q6 w - - 0 1

As a composer, I only need the WDL information. The depth to win is not important for me.
So I basically want only the WDL tables, not the DTZ.

In chess studies, the 50 move rule is not used. This is why the proposed DTZ50 is not useful for me, or to the other chess composers. In my view, the first priority is the generation of the WDL tablebases for the obvious practical reasons. This is doable in relatively short time - if somebody writes...