Another variation would be that the player, who reaches initial position
first, wins. The game can start e.g. with white King on a1 and black one
on h8 (or other postions to deversify the game). Then black starts with
undoing the last move. As 'uncapturing' of pieces is disadvantageous and
would never made otherwise, then it should be obligatory to 'uncapture',
if possible. So the game could start (black moves are shown before white
also in notation):
-1. kg8 (*Qh8) // black uncaptures white queen, undoing the last move
kg8xh8.
-1. ... Qf6 (*nh8) // white undoes Qf6xh8
-2. nf7 (*Rh8) Rh1 (*bh8)
-3. bg7 (*Rh8) Rh2 (*rh8)
. . . etc.
I need to think something more about uncapturing of pawns, but may be no
restriction should be made here, so that if e.g. white leaved with doubled
pawn and all black pieces already on the board, then white can't win
anymore. If black in the same situation, then it is a draw.
There should be probably a rule for uncapture of bishops to forbid that
two bishops e.g. on light squares are produced.
