TODO

   1 Chakart :)
   2
   3 Checkered1 & 2 --> avec switch, coup roi sur roi.
   4
   5 Ambiguous chess
   6 https://www.chessvariants.com/mvopponent.dir/ambiguous-chess.html
   7 Need special highlight square --> similar to enlightened for Dark, in Board.vue
   8 Also in notation, show only dest square for "opponents ambiguous moves".
   9 Similar to Marseille-chess, white first move only 1 subTurn, do not choose a square.
  10 Then black has a free first move, then choose a square, and the process goes on.
  11
  12 (Note: could simplify Marseille FEN, just indicate turn)
  13
  14 [Sittuyin (burmese chess) --> probably not]