Dann Corbit wrote:This one (in particular) has 62 solutions:
[d]2r5/8/3b2k1/3b2r1/6p1/8/3K4/1q6 b - - acn 3779; acs 0; bm Ba2 Ba3 Ba8 Bb3 Bb4+ Bb7 Bb8 Bc4 Bc5 Bc6 Bc7 Be4 Be5 Be6 Be7 Bf3 Bf4+ Bf7 Bf8 Bg2 Bg3 Bg8 Bh1 Bh2 Kf5 Kf6 Kf7 Kg7 Kh5 Kh6 Kh7 Qa1 Qa2+ Qb2+ Qb3 Qb4+ Qb5 Qb6 Qc1+ Qc2+ Qe4 Qf1 Qf5 Qg1 Qh1 Ra8 Rb8 Rc1 Rc2+ Rc3 Rc4 Rc5 Rc6 Rc7 Rd8 Re8 Rf5 Rf8 Rg8 Rh5 Rh8 g3; ce 32762; dm 3; pv Bb4+ Ke2 Re5+ Kf2 Qe1#;
which is pretty remarkable for having only 8 chessmen on the board.
Perhaps it's a record of some kind. I think it's interesting that a position could have that many mate-in-three moves and not a single mate-in-two move.
The mate-in-four set is currently in the stew pot and should be ready soon.
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On the EPD side of things, the "ce" operator is deprecated in favor of the "pes" operator and the "acs" operator is deprecated in favor of the "te" and "tu" operators. While the "acd" and "acn" operators remain, the interpretation of their operand values is of course heavily dependent upon the analyzing program.
For the mate-in-three set, the "dm" operand values are all "3" and are set prior to analysis. And also for this set, the "pes" operand values are all "MateIn3" and are set by the analyzing program.
The semantics for the "bm", "pv", and "dm" operators that appear above remain the same.
In all of the EPD suites that I'll deliver, each record will have an "id" operation and its single operand will always be a symbol and never a quoted string. (Operator "name" is used for a string identification operation.) In a break with tradition, the synthesized suites will be zero indexed and the "id" symbols will be a concatenation of the file name base, a period, and the record ordinal:
Code: Select all
id checkmates.00000;
id checkmates.00001;
...
id checkmates.99999;
