What's wrong with this EPD?

[Dann Corbit]

'Annoying' would describe it better than 'clever'! If it really refuses it for this reason, it is just needlessly restricting its usefulness to the user. Nothing worse than pedantic software...

There is something worse: software that crashes. An engine should reject what it cannot handle, but not more than that. For instance, if an engine has a data structure that admits up to 16 pieces per side and no more, it should reject positions with 17 pieces, otherwise, it will sooner or later crash. On the other hand, there is no reason to reject a position based on a clever retrograde analysis. Most likely, the internal data structures could handle that position. I agree with you in the latter case. However, in many cases, it is not pedantry, it is an acknowledgment of the limitations.

Miguel

I agree with both positions. I think that Abillo positions are tons of fun, though many cannot be achieved in retrograde perspective and so it is a shame to not process them (some engines do refuse). On the other hand, we cannot expect a chess position with 31 white queens and 31 black queens together with one king each to be processed successfully by a chess engine.

Out of idle curiosity, is there any chess engine that will accept and attempt to process this 'chess position'?
[d]qqqqkqqq/qqqqqqqq/qqqqqqqq/qqqqqqqq/QQQQQQQQ/QQQQQQQQ/QQQQQQQQ/QQQQKQQQ w - -

[UncombedCoconut]

Komodo and Spark will both try to analyze it. Quiescence search is difficult in such a position, so the iterations are slow.

[sje]

The closest the CIL toolkit will do is:
[D]rnbqkbnr/qqqqqqqq/8/8/8/8/QQQQQQQQ/RNBQKBNR w KQkq - 0 1
The moves are:

Code: Select all

* (setf p (string->pos "rnbqkbnr/qqqqqqqq/8/8/8/8/QQQQQQQQ/RNBQKBNR w KQkq - 0 1"))

rnbqkbnr/qqqqqqqq/8/8/8/8/QQQQQQQQ/RNBQKBNR w KQkq - 0 1
* (generate-canonical p)

(Na3 Nc3 Nf3 Nh3 Qa6 Qaa3 Qaa4 Qaa5 Qab3 Qac4 Qad5 Qae6 Qaxa7 Qaxf7+ Qb5 Qba3
 Qbb3 Qbb4 Qbb6 Qbc3 Qbd4 Qbe5 Qbf6 Qbxb7 Qbxg7 Qca4 Qcb3 Qcc3 Qcc4 Qcc5 Qcc6
 Qcd3 Qce4 Qcf5 Qcg6 Qcxc7 Qcxh7 Qda5 Qdb4 Qdc3 Qdd3 Qdd4 Qdd5 Qdd6 Qde3 Qdf4
 Qdg5 Qdh6 Qee3 Qee4 Qee5 Qee6 Qfb6 Qfc5 Qfd4 Qfe3 Qff3 Qff4 Qff5 Qff6 Qfg3
 Qfh4 Qfxa7 Qfxf7+ Qg4 Qgc6 Qgd5 Qge4 Qgf3 Qgg3 Qgg5 Qgg6 Qgh3 Qgxb7 Qgxg7 Qh5
 Qhd6 Qhe5 Qhf4 Qhg3 Qhh3 Qhh4 Qhh6 Qhxc7 Qhxh7 Qxd7+ Qxe7+)

[Evert]

Out of idle curiosity, is there any chess engine that will accept and attempt to process this 'chess position'?
[d]qqqqkqqq/qqqqqqqq/qqqqqqqq/qqqqqqqq/QQQQQQQQ/QQQQQQQQ/QQQQQQQQ/QQQQKQQQ w - -

Jazz will do it happily, although it takes ages unless I prune SEE-equal captures and even then it's slow.

[hMx]

I suspect the problem are the two black bishops on d2 and b8, one of which must be the result of a promotion, but black still has all its 8 pawns on the board.

Just a guess, since that condition does not need a sophisticated retro computation.

Cheers,
Heiner