+https://www.chessvariants.com/crossover.dir/koopachess.html
+
+Diamond Chess [Rynd] (J. A.
+Porterfield Rynd, 1886) --> Berolina2 ?
+https://www.chessvariants.com/rules/diamond-chess
+
+Bicolour Chess (Gabriel Authier, 1958). v1 et v2 : (Roméo Bédoni, 1958)
+Kings are subject to check and checkmate by
+own as well as opponent’s pieces. The Q and
+QN are interchanged in the array
+.
+v2: y but a player may capture his
+own men (TODO: only v2?)
+
+Koth : king of the hill, king cannot move into check, giving check is forbidden (no checkmate).
+
+Berolina Grid Chess, also known as
+Gridolina (originator not noted). A
+combination of Berolina and Grid Chess.
+Better than Grid Chess since Berolina pawns
+cross grid lines more easily. Described in
+World Game Review 10 as the most popular of
+the NOST combination games. (Nost-algia
+150, also Nost-algia 112 ‘not seen’)
+--> pourquoi pas, mais faudra pouvoir tracer des lignes sur plateau (Ball, Koth, Sittuyin, celle-là, Rococo)
+
+Contact (quoted by David Silverman, 1971).
+White puts a knight on any square of an empty
+chessboard. Black moves the knight and
+places a marker on the square vacated. Play
+alternates. The knight may only be moved to
+vacant squares. The object is to make the last
+move. The game can also be played with any
+of the other pieces. (Your Move)
+
+https://www.chessvariants.com/diffmove.dir/checkers.html --> move forward (Multhopp)
+in 1974 by Hans Multhopp
+https://www.chessvariants.com/diffmove.dir/checkers.html