Probably a stupid question, but I use XBoard with Fairy-Max or GNU Chess. In the edit game mode, or in analysis mode, it is not possible to castle under any circumstances. Is there some setting I am missing?

Edit: Here is an example:

For the position: 1.e4 e5 2.Nf3 d6 3.d4 Nf6 4.Nc3 Nc6 5.Bc4 Be7

I would like to play 6.O-O. Typing the move in returns "{White mates} 1-0". Dragging the king over two spaces returns "illegal move". Doesn't matter which engine is selected. I can castle while playing against the computer, however.

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  • 1
    It would be helpful if you provided an example position under which you want to castle, as well as how you try to perform the move (i.e. which piece you try to move and to which square). Jun 23, 2015 at 10:45
  • 3
    Do you set up a position? If you do that you may have to specify the castling rights. Jun 23, 2015 at 10:53

1 Answer 1


According to XBoard's manual [ref. 1]:

"...XBoard 4.2.7 and earlier... The internal move legality tester
[had problems with] castling or en passant-capture rights."

If you're running 4.2.7 (or earlier), then a newer release should solve this problem.

Caution:  Although this is not relevant to the specifics of the question, I feel that if you are running this version, then it would be remiss of me were I not to mention that there is also a reported security risk (mid-grade: stack overflow) inherent to XBoard 4.2.7 [ref. 2, 3].


  1. https://www.gnu.org/software/xboard/manual/xboard.html#Limitations
  2. https://www.cvedetails.com/vulnerability-list/vendor_id-2551/product_id-4447/version_id-19153/Tim-Mann-Xboard-4.2.7.html
  3. http://seclists.org/fulldisclosure/2004/Mar/40

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