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I think you can do better by testing for alignment first, and only then doing a lookup for the actual piece (your xxxAttacksBB functions) if there is alignment. You probably also want to do that in a ray-direction way, rather than by full rank/file/diagonal. You can cache the attack information for ...

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I think it's important to make a distinction between opening and end game values. I can imagine Crab/Barc beating a Knight in the end game simply because the Knight cannot easily defend both flanks. I also believe that the value difference between Q and B/R goes down in the end game. What would be a...

But suppose you replace Pawns by (promoting) Ferzes (or allow FIDE Pawns to capture backwards, fmWcF). These make chains that are self-protecting, and can only be damaged at the expense of the first attacker. So it would be more helpful to have two pieces, one of which less valuable than a pair of ...

Seems contrived on a normal board, normal rules and an otherwise balanced army. It would imply that B and C are due some sort of synergy bonus (generalised pair bonus) that is larger when the pieces are further apart (or at least, not on the same square). The effect HGM mentions is of course also im...

Curious about how others have implemented calculation of how many times each piece has moved since the beginning of the game. The concern is when a piece has been captured in a make move and then uncaptured and updating the array. How did you solve this? I'd do it the same way I handle the 50-move ...

You should be able to use the same logic as for pawn duo's and hanging pawns (there's a breakdown of the logic on CPW). Essentially you have to find squares that border exactly one empty square, which can be done by testing for squares that have an empty square to the West (say), but not in any of t...

With current move ordering heuristics, you get a cut-off from the first three moves in 95-99% of cases. That's the statistic you have to beat. Any effort spent on move ordering in ALL-nodes is wasted. Any effort in improving move ordering in a CUT-node is wasted in 95-99% of cases, so whatever you p...

Ok, so I'm sure I've asked this before, but I don't remember the explanation and I can't find it using the search. Assuming I have N-piece DTM and DTZ50 tables. Can't I get DTM50 optimal play (not value) by first reducing the move list to those moves that preserve the win (according to DTZ50), and ...

DTM50 conceptually stores a distance-to-mate value for each pair (position, rule50_counter). So that is 100x as much raw data as for DTM. The sequence of values for a particular position is far from random, but it is not immediately obvious how to find an efficient encoding that fits into a good co...