This chess variant was invented by L. Legan from France in 1922 when it was described in The Chess Amateur magazine.
The game uses the standard Chess set of pieces which are placed to this starting position:
The game is played with the standard Chess rules but there are several exceptions:
Pawns move one space diagonally forward and capture pieces one space horizontally or vertically in the "move direction". It means (from white's perpective, as on the above picture) that a white pawn can move only one space up-left and capture enemy pieces on adjacent squares up and left, a black pawn moves one space down-right and can capture on adjacent squares down and right.
There are no castling and no en passant moves.
Pawns can promote on the promotion zones which are set by initial positions of opponent's king, knights, bishops and rooks. In other words, a white pawn would promote on A5, A6, A7, A8, B8, C8 and D8 squares, a black one can do the same on E1, F1, G1, H1, H2, H3 and H4 squares.