In chess positions, a similar sequence of moves starting from a slightly different position would result in a completely different position. For example, imagin

In chess positions, a similar sequence of moves starting from a slightly different position would result in a completely different position. For example, imagine playing 10 moves identically in two games, but in one of them, 20 moves ago, a bishop moved into some corner that causes a piece to be pinned. This means that the right move would be completely different between these two scenarios despite the last 10 moves being the same. To play well, the model would need to keep track of where the pieces are and be able to "reason" about the situation to some extent. I've also tested it with some rare and unorthodox openings. For example, after 1. f3, there are only a handful of games on chessgames.com (which has over a million games), and after several more moves it's easy to get a position where even large online sites like chess.com and lichess.org don't have any games at all. Even in such cases, parrotchess was able to navigate it fairly decently despite never having ever seen that position before.