TalkChess.com

[Karatorian]

I'm developing a Shogi Engine for the Game Boy Advanced. As the GBA has a very small amount of memory (32k CPU internal, 256k external), I haven't bothered with transposition tables or hashing of any kind as of yet.

The engine has implemented pretty much all of the rules of Shogi, except those related to repetition. The rules for repetition in Shogi are pretty similar to those of chess, except that four-fold, rather than three-fold repetition is required to draw, and that giving perpetual check is a loss for the check giver.

The techniques I've read about for repetition detection involve either storing some info in the transposition table, using a dedicated hash table, or using a list of hashes of previous positions. In all cases, this requires hashing to be implemented.

Due to the limited memory availible on the GBA, I'm not sure if I'm going to bother implementing a transposition table. In that case, I'm not sure I really want to implement hashing at all, as it's likely to slow down my move making and unmaking functions.

Furthermore, as there's no concept of a halfmove clock in shogi, one cannot use that to reduce the depth of the history list one needs to search.

So I was wondering if anyone could point me at an alternative scheme for detecting repetitions. Or am I just being silly? Is there enough memory availible to make a transposition table workable, so I should just implement hashing?