It is difficult to say that is not impressive due to it being an emergent ability.
I don't know why you think it's an emergent ability.
It's seeing a sequence of moves, and playing the most likely next move (i.e. the most likely next token) given the previous complete move sequences it was trained on. That's the baseline of what an LLM does—not something emergent. Games in online chess databases tend to be of relatively good players. Nobody wants to look up games played by two 800 ELO players.
As an aside, there have been chess programs for years that show you for a given position all of the previous games in its database with the same position and the win outcome % of each move. That's all that's going on here.
It could be, but would you think that of the 100-300 bn parameters in the model a lot are dedicated to chess move sequences? It seems likely that it has seen such data, but I would be surprised if it is using a considerable chunk to store chess database information.
Chess moves are a tiny/diminute part of all text learned by the model. This memorization argument is very similar to the "Stable Diffusion just takes bits of the images in the original dataset and parches them together".
1400s on chess.com never play illegal moves. 300s on chess.com never play illegal moves. Because it's impossible to do. In the real world, even grandmasters can make illegal moves, though they almost always have to be under time pressure.
This idea that the illegal moves completely invalidate this result is just ill-conceived. On the other hand I do agree this is mostly returning common sequences of moves. And if you actually analyse the games, especially the ones with illegal moves, you'll find plenty of qualitative evidence of that. But I'm fed up of doing people's thinking for them for today, so this is peace out for me today. See my others comments on this post to see a more detailed analysis of what this is doing.
People are always telling me that I'm moving the goalposts when I challenge the hyperbole about LLMs. But now you're moving the goalposts about chess.
Not playing illegal moves is a pre-requisite for any strong understanding of how to play chess. That is definitely the goal post.
It's not like an AI making silly mistakes when driving a car.