[phonebucket]

Traditional chess engines excel at tactics. But most chess tactics are brute forceable, and traditional chess engines are normally brute force behemoths.

Large language models have tradtionally been very weak at brute force computing (just look at how bad they are at multiplicaion of large numbers). If it can somehow excel at something which typically involves computing power like chess tactics deep into a game well after a novel position has been reached, then put me down as impressed.

[mtlmtlmtlmtl]

I'm impressed too, but only in the sense that I'm surprised that transformers can reach any level of success at all.

But it seems mostly like a weird statistical quirk of chess that somehow tactical sequences are the most common move sequences in chess(except for openings), and so they're very likely to pop out from a model predicting the most likely tokens. But there doesn't seem like there's a reasonable path from doing that to being able to determine whether a likely tactical sequence is actually a good idea. I've been thinking a lot about ways to use a transformer model in combination with search to accomplish this for a few days now. So far I have a few ideas, most of them are a lot less revolutionary than I was hoping for.

You could take a (narrowly trained) transformer model, give it the game so far and have it predict a sequence of moves. Then use those moves as a move ordering heuristic in a good old stockfish like architecture. Essentially do the normal Alphabeta search but look at the suggested moves first at each node, indexed by ply. I could imagine if the suggestions get really good, this might prune a decent amount of nodes. But nothing earth-shattering, maybe 50 elo gains at most is my intuition there. I have other non-transformer ideas that I think are more worthwhile to work on for now.

The other is to instead invoke it at every node asking for one move only, and guide a search that way. But this somehow just feels like a reinvention of LCZero.

There's a third more speculative idea which would involve a novel minimax search algorithm inspired by how humans think in terms of tactical sequences, but this idea is still so vague in my head I'm not even sure how to coherently describe it, let alone implement it, or whether it makes sense at all.

I still need to think about this more deeply, break out my whiteboard and play with some minimax trees to flesh it out. It is intriguing though. I'd also have to train my own transformer; I see no reason to actually end up using GPT for this. Seems to be no sense including the entire internet in your data if all you're doing is predicting sequences of algebraic notation.

[YeGoblynQueenne]

If you just want to learn a model of chess games in algebraic notation (is that what it's called? I don't play chess) then you don't need to train a Transformer. That would be overkill, and you wouldn't really be able to train it very well. I mean, unless you have a few petaflops of compute lying around.

You could instead start with a smaller model. A traditional model, like an n-gram model, a Hidden Markove Model (HMM) or a Probabilistic Context Free Grammer (PCFG). The advantage of such smaller model is that they don't need to have billions of parameters to get good results, and you'll get more bang for the buck of the many, many, many examples of games you can find.

But, don't expect to get very far. A system that learns only to predict the best move will never beat a system that looks ahead a few dozen ply, with alpha-beta minimax, or that plays out entire game trees, like Monte-Carlo Tree Search. Well, unless you do something silly to severely hobble the search-based system, or train the predictive model with all possible chess games. Which I mean, is theoretically possible: you just need to build out an entire chess game tree :P

You could also try with a simpler game: Tic-Tac-Toe should be amenable to a predictive modelling approach. So should be simpler checker-board games like hexapawn. Or even checkers, which is after all solved.

But my question is, what would you hope to achieve with all this? What is the point of training a predictive model to play chess? Hasn't this been tried before, and shown to be no good compared to a search-based approach? If not, I'd be very surprised to find that out, and there might be some merit in trying to test the limits of the predictive approach. But it's going to be limited alright.