Ideas to try

[Sopel97]

• Try using an index into an ordered list of legal or pseudo legal moves. Could save 0.5-1 bits per move. This is a questionable change because it would make move encoding much slower.

• Try to reduce the magnitude of encoded score differences when encoding subsequent positions by using some form of prediction.

• Adaptive block size for variable length encoding of scores

• Reintroduce compression on top? Could reduce the size by further 5-10%