Illegal move "g8i8"

[capa12x10]

I'm playing Capablanca random variant against ArcBishop80 chess engine, and WinBoard is reporting an Illegal move "g8i8" after Black tried to castle.

Here is a screenshot of the board:
https://1drv.ms/i/s!AtRNzrUtkzspgoQg4HF ... Q?e=ROiQhj

And here is the position in FEN format: (it's Black's turn)
https://www.filemail.com/d/htfjfawfdgkhlqf

I tried the same position in Cute Chess program and it accepted this move as valid.

Is this a bug in WinBoard or am I doing something wrong?

[H.G.Muller]

How did you try to enter the move? For Fischer castling you should first click the King, and then the Rook you want to castle with. If legality testing is on it would highlight the friendly Rook as possible destination, not the King destination square. For moves by the engine, the castling should be specified as O-O, not as the King move. So this could be a problem with Archbishop80.

[capa12x10]

Yes, ArcBishop80 tried to move the King from g8 to i8 instead of O-O. Perhaps Winboard could be updated to accept this move as valid and then treat it as O-O?

Here is another problem:
Again, the same position: br2q1kr1n/ppp3pppp/4pp3c/1n1p6/1Q3P4/1P1P4P1/PBP1P1PPCb/1RNB2KR1N b HBhb - 1 1

This time I set Fairy-Stockfish to play White. I try to castle manually by first clicking the King, and then the Rook. I get this error:

Illegal move "O-O" (rejected by first chess program)

The same move tested in Cute Chess works fine.

Here are the screenshots:

https://1drv.ms/i/s!AtRNzrUtkzspgoQpsF8 ... A?e=8PbKT1
https://1drv.ms/i/s!AtRNzrUtkzspgoQqdo2 ... Q?e=fqNNB8

[H.G.Muller]

Well, if WinBoard says 'rejected by engine' that means it did understand the move you entered correctly as a castling. It is just that Stockfish apparently doesn't allow you to castle in this position. This seems a Stockfish problem.

This is a bit strange, as I have tried it with the version of Fairy Stockfish I had on my PC (probably an old one, 11.2 LB 64), and it works fine. I started WinBoard, selecting Fairy Stockfish as WB engine from the startup dialog, set it to play CRC through the New Variant dialog, pasted your FEN,, and it allows black to castle without problems.

[capa12x10]

OK, it is Fairy-Stockfish issue.

This is from Fairy-Stockfish developer:

"Yes, Fairy-SF currently only understands the normal castling notation in the CECP/xboard protocol, not the FRC notation. The CECP documentation states that
Castlings are indicated as the King move, e.g. e1g1 or e8c8, except for Fischer castling, which is O-O or O-O-O (oh, not zero!).
In UCI that all works fine, therefore other GUIs have no issue."

[H.G.Muller]

Well, you could try to run Fairy Stockfish as UCI engine. Probably many other things won't work then, because they are not supported by UCI, but for CRC it would probably be fine.

[Jasonb123]

This is likely a bug in WinBoard since it's not accepting a legal move that other chess software, like Cute Chess, recognizes. https://www.stpaulpressurewash.com/retaining-wall-washing-twin-cities-mn

[H.G.Muller]

Nope. It is more likely a Cutechess bug when it understand a move notation in a way different from what the communication protocol prescribes it should mean.