Gomoku, also called Five in a Row, is an abstract strategy board game. It is traditionally played with Go pieces (black and white stones) on a Go board.
Players alternate turns placing a stone of their color on an empty intersection. Black plays first. The winner is the first player to form an unbroken line of five stones of their color horizontally, vertically, or diagonally.
In some rules, this line must be exactly five stones long; six or more stones in a row does not count as a win, and is called an overline.
If the board is completely filled and no one can make a line of 5 stones, then the game ends in a draw.