A chess variant with four armies advancing into the board from four directions, but with adjacent pairs of armies allied. Thus White has a so-called "round front" and a "square front", advancing north and west respectively, while Black has a "round front" and a "square front" advancing south and east. All four armies take turns to play, so each player on their turn first makes a move with one of their square-front pieces, then with one of their round-front pieces. The object of the game is to capture both enemy kings. When one king is captured, the other pieces of the corresponding army disappear, so the player can play on but with only half their pieces. From 2007 through 2010 the game was promoted through a website at playfrontiers.com.