+Rampage Chess: Any Unit May move to any empty square that is guarded. A King cannot make a special move to get out of check.
+
+https://www.chessvariants.com/rules/pacifist-chess (1 et 2, utilisant somme values ou nb pièces)
+
+Swap chess: Friendly pieces may swap places
+
+https://www.chessvariants.com/crossover.dir/koopachess.html
+--> Can a stunned piece capture? Maybe not. ...recover? After 5 moves? Never?
+