Enhancement request: Chess960 castling rules

[LeviBarnes]

I had hoped to use Tarrasch to analyze some Chess960 games. Because the start position is not standard, the header includes a FEN for the initial position. Like this:

[Event "Chess.com 960 friendly"]
[Site "Chess.com iPhone"]
[Date "2022.12.31"]
[Round "?"]
[White "dyado72"]
[Black "fizixgeek"]
[Result "1-0"]
[FEN "qrnknbbr/pppppppp/8/8/8/8/PPPPPPPP/QRNKNBBR w HBhb - 0 1"]
[WhiteElo "920"]
[BlackElo "1457"]

When I load in Tarrasch, it shows the standard opening position and can only play a few moves before reaching an illegal move and getting stuck.

This feature request is for support for FEN in .pgn headers.

[billforsternz]

Sorry about that, Tarrasch has no trouble with FENs in PGN headers The problem here is different, Tarrasch does not support Chess960. The reason is the castling rules. One day I'll add support. I'll accept this message as a feature request for that.

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On Sun, 8 Jan 2023, 19:50 Levi Barnes, ***@***.***> wrote: I had hoped to use Tarrasch to analyze some Chess960 games. Because the start position is not standard, the header includes a FEN for the initial position. Like this: [Event "Chess.com 960 friendly"] [Site "Chess.com iPhone"] [Date "2022.12.31"] [Round "?"] [White "dyado72"] [Black "fizixgeek"] [Result "1-0"] [FEN "qrnknbbr/pppppppp/8/8/8/8/PPPPPPPP/QRNKNBBR w HBhb - 0 1"] [WhiteElo "920"] [BlackElo "1457"] When I load in Tarrasch, it shows the standard opening position and can only play a few moves before reaching an illegal move and getting stuck. This feature request is for support for FEN in .pgn headers. — Reply to this email directly, view it on GitHub <#39>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ABSQYSTVKQCWXOJL5LPWAMLWRJPULANCNFSM6AAAAAATUM56S4> . You are receiving this because you are subscribed to this thread.Message ID: ***@***.***>

[LeviBarnes]

No need to be sorry. Great software!

Maybe my header is wrong, but when I load the attached file, and play through either of the last 2 games (the Chess960 games), the board starts in standard position and I can only play until a move that's illegal without the alternate starting position. Is the .pgn wrong?

Full disclosure, I haven't tried building from the source code yet. Running V3.13b-Windows.

Also, do you know whether the engines support the Chess960 castling rules?

fizixgeek.zip

[LeviBarnes]

Ach. Wait! It's the castling status in the FEN. Changed to KQkq and the board looks good.

Oh, and it looks like Stockfish, at least, castles correctly in Chess960.

official-stockfish/Stockfish#2405

[billforsternz]

Ok, makes sense. I suspected your FEN was slightly illformed but I'm on mobile and unable to experiment or drill down at all. I was going to suggest you try the "shuffle chess" feature I put in the setup position feature; basically to let our chess club captain generate Chess960 positions with Tarrasch. Setup a position that way, make a few moves (no castling! It's not the same as proper Chess960 support), save as PGN and compare to what you have. Anyway yes, Stockfish definitely has Chess960 support, although I thought it needed a special UCI option/flag to trigger it. Bill.

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On Mon, 9 Jan 2023, 21:30 Levi Barnes, ***@***.***> wrote: Ach. Wait! It's the castling status in the FEN. Changed to KQkq and the board looks good. Oh, and it looks like Stockfish, at least, castles correctly in Chess960. official-stockfish/Stockfish#2405 <official-stockfish/Stockfish#2405> — Reply to this email directly, view it on GitHub <#39 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ABSQYSSIWER266YXMDXIATTWRPEDBANCNFSM6AAAAAATUM56S4> . You are receiving this because you commented.Message ID: ***@***.***>