[leelin]

Chess.com has the "personality bots" that supposedly play with the style of various well-known players, streamers, and GMs.

But I remember watching Hikaru Nakamura stream once playing through each of these bots (and beating them fairly easily). He commented that several of the bots were doing things the real players would never do, both in style and even the opening move (1.e4 for a player that almost always opens 1.d4)

It was fairly early after the personality bots came out, so maybe they've fixed it by now.

[marcodiego]

Chessmaster 3k had that feature. But I was never good enough in chess to evaluate how well it worked. Still, I thought about the simplest method:

  - get a chess playing algorithm (I think it will probably well with minimax or mcts) with many tunables,

  - use a genetic algorithm to adjust the tunables of the first algorithm; use how similar it plays (make it choose a move on positions from a database of games from said player) as a goal function.

Doesn't seem terribly complicated to do, but don't know how similar to a human it would play.

[8note]

My guess on the personality bots is that they set the bot to play at the players' current rating, not training ml based on the games.