size
command-line option when you start up XBoard for such variants to be playable.
You can overrule the default board format of the selected variant,
(e.g. to play suicide chess on a 6 x 6 board),
in this dialog, but normally you would not do that,
and leave them at '-1', which means 'default'.
The game file parser will accept PGN (portable game notation),
or in fact almost any file that contains moves in algebraic
notation.
Notation of the form ‘P@f7’
is accepted for piece-drops in bughouse games;
this is a nonstandard extension to PGN.
If the file includes a PGN position (FEN tag), or an old-style
XBoard position diagram bracketed by ‘[--’ and ‘--]’
before the first move, the game starts from that position. Text
enclosed in parentheses, square brackets, or curly braces is assumed to
be commentary and is displayed in a pop-up window. Any other
text in the file is ignored. PGN variations (enclosed in
parentheses) also are treated as comments;
however, if you rights-click them in the comment window,
XBoard will shelve the current line, and load the the selected variation,
so you can step through it.
You can later revert to the previous line with the ‘Revert’ command.
This way you can walk quite complex varation trees with XBoard.
The nonstandard PGN tag [Variant "varname"] functions similarly to
the -variant command-line option (see below), allowing games in certain chess
variants to be loaded.
Note that it must appear before any FEN tag for XBoard to recognize
variant FENs appropriately.
There is also a heuristic to
recognize chess variants from the Event tag, by looking for the strings
that the Internet Chess Servers put there when saving variant ("wild") games.
oldSaveStyle
option is true, in which case they are saved in an older,
human-readable format that is specific to XBoard. Both formats
can be read back by the ‘Load Position’ command.