A one-dimensional (played on a line) variation of Go that was first described by A.K. Dewdney in his book The_Planiverse. In 2001, Alan Baljeu modified the game into its present form.
The rules (from Wikipedia):
Black and white take turns placing stones on the line. Unlike Go, this placement is compulsory if a move is available; if no move is possible, the game is over.
No stone may be placed in a location occupied by another stone, or in a location where a stone of your own colour has just been removed. The latter condition keeps the game from entering a neverending loop of stone placement and capture, known in Go as ko.
If placing a stone causes one or two groups of enemy stones to no longer have any adjacent empty spaces--liberties, as in Go--then those stones are removed. As the above rule states, the opponent may not play in those locations on their following turn.
If placing a stone causes one or two groups of your own colour to no longer have any liberties, the stones are not suicided, but instead are safe and not removed from play.
Play continues until a player cannot place a stone on their turn. At this point, the number of stones on the board is counted; the winner is the one with the most stones.