Chad (1982)

Chad was designed as an attempt to distill Chess to what the designer considered its essential aspect - the mate - and whatever was necessary to support this. It is played on a 12x12 square grid with two "castles" marked off; these are 3x3 regions which have 1x3 "walls" on all sides. Each player has a king and eight rooks, all of which start in their castle. Rooks move as in Chess but cannot capture in general; a rook may only capture another rook if one is in its own castle and the other is on one of the walls of that castle. However, a rook can put a king in check from any distance. Kings can move as either kings or knights, but are confined to their own castles. They can always capture.