Using the probability distribution of moves at any given position, so that more likely moves take less space, will result in saving space on average. This is t

Using the probability distribution of moves at any given position, so that more likely moves take less space, will result in saving space on average. This is the same as Huffman coding, just applied to a different domain. For that matter, it might also resemble LLM compression of input text, although LLM compression is intentionally lossy and the above schemes are not.