the basis of this algorithm is to rank the possible moves from the current position, then use that to choose a Huffman encoding. In essence, they use a very naive single-move-look ahead chess AI to quickly rank moves giving them a crude measure for how ‘surprising’ a particular move would be at that point in the game.

Interesting question: If you just generated the bit string that corresponded to taking the ‘most obvious move’ according to their heuristics, what game would that play out? In a way, that would be the ‘most obvious chess game’, or perhaps the ‘least creative chess game’...

In theory a more optimal version would be to use a more sophisticated AI to rank the next moves, and even to choose how aggressively to Huffman code the possible options.

In a sense this would measure the information content of a chess game (at least relative to the ‘knowledge’ of that AI) . I wonder what the variance in the number of bits needed to encode various games would tell you about the play style of different players, or the nature of the game, or even the relationship betweeen information theory and creativity....