>A separate comment: I wonder if the time efficiency issues mentioned are really that severe? Since the problem is so small/finite. Just noticed this. The beau

>A separate comment: I wonder if the time efficiency issues mentioned are really that severe? Since the problem is so small/finite. Just noticed this. The beauty of my "sweet spot" scheme is that processing these 8 bit moves is almost as quick as processing a straightforward normal move representation (32 bits in my code because I store extra information to make moves "undo-able" - although 16 bits is reasonable). This is important for some of the things I want to do - For example I am experimenting with the idea of implementing a query to search a database of games for a position by literally playing through every game looking for the position (actually the hash of the position). The standard approach is (I think) to index all the positions in the database - which swells the database a lot. If you do a little math you'll see that you need the move processing to be lightning fast for this to be responsive in a multi-million game database. Move processing involving generating move lists in every position would leave the user waiting minutes (maybe hours!).