The author is looking for positions which are difficult for low rated players and easier for high rated players.
Poor man’s version of this which requires no training would be to evaluate positions at low depth and high depth and select positions where the best move switches.
Training neural nets to model behavior at different levels is also possible but high rated players are inherently more difficult to model.
basically, the state space of the game can produce some intuition on why certain games are hard, and is demonstrated as a clustering of various states that are only linked to the winning state by a very small number of edges. So a player can easily "get lost" in the maze.
FacelessJim · 2h ago
This reminds me of a little project [1] I had fun with to try and compute the sharpness of a position and/or evaluate whole lines. Indeed, the notion of sharpness (which I believe it’s different from complexity) although easy to intuit I’ve never found a satisfactory implementation.
As a player I like to think of sharpness as a measure of the potential consequences of a miscalculation. In a main line dragon, the consequence is often getting checkmated in the near future, so maximally sharp. In a quiet positional struggle, the consequence might be something as minor as the opponent getting a strong knight, or ending up with a weak pawn.
Whereas complexity is a measure of how far ahead I can reasonably expect to calculate. This is something non-players often misunderstand, which is why they like to ask me how many moves ahead I can see. It depends on the position.
And I agree, these concepts are orthogonal. Positions can be sharp, complex, both or neither. A pawn endgame is typically very sharp; the slightest mistake can lead to the opponent queening and checkmating. But it's relativity low in complexity because you can calculate far ahead using ideas like counting, geometric patterns(square of the pawn, zone of the pawn, distant opposition etc) to abstract over long lines of play. On the opposite side, something like a main line closed Ruy Lopez is very complex(every piece still on the board), but not especially sharp(closed position, both kings are safe, it's more of a struggle for slight positional edges).
Something like a king's indian or benoni will be both sharp and complex. Whereas an equal rook endgame is neither(it's quite hard to lose a rook endgame, there always seems to be a way to save a draw).
nomilk · 2h ago
Interested to read the code, but the link provided 404s
Amethyst-Cat apparently erased their github account, but the internet archive still has one snapshot [1]. The pdf link from there redirected to the davidtpeng account, but
that github user no longer has a ChessComplexity repo and the internet archive only has a broken snapshot [2].
Poor man’s version of this which requires no training would be to evaluate positions at low depth and high depth and select positions where the best move switches.
Training neural nets to model behavior at different levels is also possible but high rated players are inherently more difficult to model.
basically, the state space of the game can produce some intuition on why certain games are hard, and is demonstrated as a clustering of various states that are only linked to the winning state by a very small number of edges. So a player can easily "get lost" in the maze.
[1] https://github.com/ghyatzo/stockfish-line-sharpness
Whereas complexity is a measure of how far ahead I can reasonably expect to calculate. This is something non-players often misunderstand, which is why they like to ask me how many moves ahead I can see. It depends on the position.
And I agree, these concepts are orthogonal. Positions can be sharp, complex, both or neither. A pawn endgame is typically very sharp; the slightest mistake can lead to the opponent queening and checkmating. But it's relativity low in complexity because you can calculate far ahead using ideas like counting, geometric patterns(square of the pawn, zone of the pawn, distant opposition etc) to abstract over long lines of play. On the opposite side, something like a main line closed Ruy Lopez is very complex(every piece still on the board), but not especially sharp(closed position, both kings are safe, it's more of a struggle for slight positional edges).
Something like a king's indian or benoni will be both sharp and complex. Whereas an equal rook endgame is neither(it's quite hard to lose a rook endgame, there always seems to be a way to save a draw).
https://github.com/Amethyst-Cat/ChessComplexity/blob/master/...
[1] https://web.archive.org/web/20201226113203/https://github.co...
[2] https://web.archive.org/web/20240316015417/https://github.co...