Three-handed chess: Waider's game

There have been many chess variants, that were designed for three persons. This is one of the oldest ones (although Marinelli's three handed chess, or Triple Chess is about a century older). It was invented by Waider in 1837. The game is mentioned in Pritchard's Encyclopedia of Chess Variants.

Rules

The board is as shown below, with the opening setup.

Note that queens are always at the left side of kings in the opening setup.

Pieces may change direction when they cross the boundary lines between the three different `parts' of the board. When a player is mated or stalemated, his pieces are frozen: they cannot be moved, nor be taken. When the mate is released, the player can continue to play, and his pieces can be taken again. The game is won by mating the other two players.