- About 'Dual King Chess':
'Dual King Chess' includes two games, 'Dual Chess' and 'Weak Dual Chess'.
In this game, there are two Kings on the board instead of a Queen.
In 'Dual Chess', a player must checkmate the either of two enemy's Kings.
In 'Weak Dual Chess', a player must capture the both of two enemy's Kings.

Any of Kings can 'castle' to the both side directions.
But in order to castle with both, these should be short castlings.

A Pawn can also promote to a King instead of a Queen.
The check-rule applies also to the King which a Pawn promoted to.

- Objective of 'Dual Chess': To checkmate the opponent's either of Kings by attacking it so it can not escape.

- Objective of 'Weak Dual Chess': To capture actually the opponent's both Kings by attacking.

- Game and Variants:
This zrf file includes one game(#1) and one variant(#2).
In all the variant, White is the first player.
In order to play with Black which is the second player, it is need to press both the 'Switch Sides' button.

#1: Dual Chess
A player whose either one of Kings was checkmated will lose.

#2: Weak Dual Chess
A player whose both of Kings was captured will lose.