Support for very large boards (>12x10)

[ianfab]

Place to discuss potential support for board sizes >12x10.

• Most likely needs to be based on 256 bitboards, i.e., up to 16x16 boards.
• Use non-magic method for move generation? Or split magics (as for rook and cannon) to reduce size?

[SGQuek]

Maybe Chu-Shogi (中将棋)?

[Snowmoondaphne]

https://gall.dcinside.com/mgallery/board/view/?id=pandemonium&no=19&page=1

Can these rules be fully implemented? I don't know if the last rules on that page can be implemented in Stockfish,,

[ianfab]

The board size as well as rules 2. and 3. are not supported. If you want to discuss it in more detail, please create a separate topic for it.

[Snowmoondaphne]

Ahh Thanks 8ㅁ8

2021년 11월 16일 (화) 오후 5:02, Fabian Fichter @.***>님이 작성:

The board size as well as rules 2. and 3. are not supported. If you want to discuss it in more detail, please create a separate topic for it.

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[Rechefiltr-is-Fire]

Maybe Horizons?

[Belzedar94]

Maybe Horizons?

If you mean https://www.chessvariants.com/rules/horizons, invented by yourself, the implementation is highly unlikely to happen since it will require:

• Very large board support (>128 bitboard)
• Alternative pawns
• Conditional rules such as "watching"
• Custom promotion rules for all the pieces
• Conditional en-passant (also, en-passant for non-pawn pieces)
• Not sure if all the Betza moves are supported for the complex pieces.

[gwahak]

Is 11x10 board supported in Fairy-Stockfish?

[gbtami]

Yes.

[ddugovic]

I too have a curiosity about Chu Shogi (playable on Lishogi)... I'm finding maintaining https://github.com/ddugovic/hachu immensely challenging (in large part since I'm attempting to refactor code to the point where I can debug and understand it; I can't tell how close I am on that front to being successful).

[ianfab]

For chu shogi there are some challenges aside of the board size, especially the lion moves, but I think these should not be a blocker once the board size limitation would be solved.

I personally very likely won't work myself on the larger board sizes in the foreseeable future though, since it would open another can of worms regarding performance and memory, unless there is some big refactoring with respect to board representation, e.g. dropping bitboards.