To select a piece, left double-click on the piece with the left mouse button. If you can move the piece, the squares where the piece can be moved to will be highlighted.
To move a piece, select it [by left double-click], then left double-click on the desired destination square.
You can move the board, rotate it, and zoom in/out:
To rotate the board, hold the left mouse button down and move the mouse.
To move the board, hold the right mouse button down and move the mouse.
To zoom in or out, hold the Control key and right mouse button down, and move the mouse up or down.
The rules used by this program were created by Jens Meder. For details, click here.
The rules may be summarized as follows:
viewing the board from above, you'll notice that some squares overlap.
From that view, piece moves are the same as in regular chess, except that you may choose which of the overlapping squares the piece will land at.
The movement of a sliding piece (bishop, rook or queen) is blocked by a piece in any of the overlapping squares; the sliding piece may land above or below the blocking piece.
Bugs and restrictions:
The game doesn't support en-passant captures yet. Additionally, pawns are automatically promoted to queens.