An m,n,k-game is an abstract board game in which two players take turns in placing a stone of their color on an m×n board, the winner being the player who first gets k stones of their own color in a row, horizontally, vertically, or diagonally. Thus, Tic-tac-toe is the 3,3,3-game and free-style Gomoku is the 15,15,5-game. An m,n,k-game is also called a k-in-a-row game on an m×n board.