What is "gomoku"

Gomoku is an abstract strategy board game. Also called Gobang or Five in a Row, it is traditionally played with Go pieces (black and white stones) on a go board with 19x19 (15x15) intersections; however, because once placed, pieces are not moved or removed from the board; gomoku may also be played as a paper and pencil game. This game is known in several countries under different names.

Black plays first if white did not just win, and players alternate in placing a stone of their color on an empty intersection. The winner is the first player to get an unbroken row of five stones horizontally, vertically, or diagonally.