orthodox king into check). Idle Kings' chess Game rules Players play without kings until after Black's 12th move, when White places his king on any open square (but not in check), and Black does the same. Additional rule After kings are placed the game continues normally, except that kings may not move, unless in check. Unirexal chess Also known as The Black King's Complaint, Unirexal variants are those with only one king on the board. "The black king disappeared, explains Parton, because he was fed up with always being mated in problems." Game rules Black has a second queen instead of a king, and must checkmate White in a reasonable number of moves (agreed to before the game), otherwise White wins. Variation Black has 20 knights, but no king. If Black does not checkmate White within 50 moves, he loses. Decimal Rettah chess This is Parton's first chess variant invention. The idea sprang from a dislike for weak kings: "The king ought to be strong, not feeble, by aesthetic standards: he is the centre around which turns the whole game itself. In consequence, my Rettah monarch is the most powerful of all pieces." Each player has two rettahs (kings) and two queens on a 10×10 board. There is no checkmate; a player wins by capturing both opponent's rettahs. Game rules A rettah [hatter spelled backwards] moves and captures as a Q+N compound. If a rettah is attacked, the attacking piece must be captured immediately. (If more than one piece is able to capture, the player may choose. An attacked rettah will always have the option to capture.) If a rettah is attacked by two pieces simultaneously, the attacked rettah must capture one of them (the player may choose which). Pawns can move up to three steps on their first move. There is no en passant. If players agree, pawns can also move one step diagonally forward (to facilitate opening lines). A pawn promotes to rettah, but only if a rettah of the same colour was previously captured. There is no castling in Decimal Rettah. Variations Parton gives several variations, although Decimal Rettah is "possibly the earlier version and arguably the better" . In Absolute Rettah chess, only a rettah may capture a rettah. (So a successful tactic involves attacking a rettah with a piece guarded by one's own rettah.) In Giveaway Rettah, Decimal or Absolute Rettah are played according to