This can be followed by some optional info to be sent to GUI when it\r
selects the variant, e.g. to tell it how some non-standard pieces move.\r
\r
+The board size can be suffixed with =n where the number n then indicates\r
+the depth of the promotion zone (which normally is just the last rank).\r
+Currently only n=3 is understood.\r
+\r
There can be upto 15 piece types per variant, numbered 1 to 15.\r
Numbers 1 and 2 are considered Pawns for white and black, respectively,\r
and the 2nd and 7th rank of the opening setup will be filled with them.\r
With a value -1, however, loss of the first piece of that type loses the game.\r
For royal piece types larger than 7 there is the special rule that it is not\r
allowed to leave more than one of them under attack ('duple check').\r
+A royal value of -2 is currently used as a kludge to enable an alternative\r
+winning condition, namely when the royal piece reaches (and survives in)\r
+one of the four central squares.\r
\r
-NOTE: piece value 181 for piece 7 is reserved for Makruk, and enables\r
-promotion on the 6th rank. Do not use it in other variants.\r
+NOTE: Any piece value that (in decimal notation) ends in '3' will not be \r
+accepted as promotion choice. (And neither will be absolute royalty,\r
+i.e. piece value -1).\r
\r
The individual bits in the move-mode descriptor have the following meaning:\r
In the last hexadecimal digit:\r