Gomoku
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, using 15×15 of the 19×19 grid intersections. Because pieces are not moved or removed from the board, Gomoku may also be played as a paper-and-pencil game. The game is known in several countries under different names.
Go variants
Tibetan Go is played on a 17×17 board, and starts with six stones (called Bo) from each color placed on the third line as shown. White makes the first move. There is a unique ko rule: a stone may not be played at an intersection where the opponent has just removed a stone. This ko rule is so different from other major rulesets that it alone significantly changes the character of the game. For instance, snapbacks must be delayed by at least one move, allowing an opponent the chance to create life. Finally, a player who occupies or surrounds all four corner points (the 1-1 points) receives a bonus of 40 points, plus another 10 if the player also controls the center point.