This game is like Stratego. This game L'Attaque along with Aviation - The Aerial Tactics Game of Attack and Defence and Dover Patrol were each designed by Harry Gibson along with a more complicated incorporation of all three, a game called Tri-Tactics
The game is played with 36 pieces each on a 9x10 square board. The Pieces' values are hidden and only revealed when they share a square when a opponent's piece. In most cases if a piece has a higher value it wins the battle. Spies, however, if attacking the Commander (highest value) wins.
Play continues until one player finds the opponent's flag piece and takes it.