They vary in areas like scoring method, ko, suicide, handicap placement, and how neutral points are dealt with at the end.
These differences are usually small enough to maintain the character and strategy of the game, and are typically not considered variants.
In some of the examples below, the effects of rule differences on actual play are minor, but the tactical consequences are substantial.
Tibetan Go is played on a 17×17 board, and starts with six stones (called Bo) from each color placed on the third line.
It became antiquated in the early 20th century when it was largely replaced by modern go due to Japanese influence.
The strength and fame of visiting Japanese professional go players encouraged Koreans to abandon Sunjang baduk.
This was supported by the father of modern Korean go, Cho Nam-ch'eol, who established close links to Japan by studying go there.
A fixed stake ("bang") is paid for every ten points on the board by which the loser is beaten.
Yasuda was inspired by the need for a medium to address the problem of bullying in Japan, but soon found that "first capture" also works as an activity for senior citizens and even developmentally delayed individuals.
In Stoical Go, invented by abstract game designer Luis Bolaños Mures, standard ko rules don't apply.
Although snapbacks are not possible in the basic variant (as it is necessary to make a ko threat before any consecutive capture occurs), they can be explicitly allowed with an extra rule while retaining the property that all known forced cycles are impossible.
Environmental Go, also called Coupon Go,[10] invented by Elwyn Berlekamp, adds an element of mathematical precision to the game by compelling players to make quantitative decisions.
In effect, the players participate in a downward auction for the number of points they think sente is worth at each stage in the game.
The professional players Jiang Zhujiu and Rui Naiwei played the first Environmental Go game in April 1998.
[12] If the said shape cannot be placed on the board, then an illegal move is deemed to have been played, which necessitates resignation.
The rules must be somewhat altered to create balance in power, as those who play first (especially the first four, on a four-cornered board) have significant advantage.
[13] There are various optional rules that enable cooperation between the players, e.g. division of captured stones among neighbors, or forming alliances for adding up territory points.
Devised by R. Wayne Schmittberger, each player is allowed to play up to four stones in a turn, provided they are solidly connected on adjacent points.
Block Go was a variant of Go played at the 20th Annual Computer Olympiad in which tetris pieces are utilized instead of go stones.
Micaël Go is a multiplayer variant originally designed in 2023 by a member of the André-Grasset College go club in Montreal, for the purpose of late night after-club team play at the local Etoh bar.
It is therefore a great opportunity for players of different levels to enjoy a game together, ask questions and share tips on how to improve.
This variation is regarded as a useful tool for developing one's memory and reading skills by forcing both players to remember who placed each stone.
An external program or a third person may be used to keep track of who captures what in case one or both players forget the true color of a stone.
The referee keeps track of the complete game and informs a player if their move was illegal, in which case they can try again.
It can be played on a computer app[26] or simulated on a standard board, but requires imagination on the part of the players to perform an abstract join at the edges.
Tactics become more elegant without the need for special border and corner cases (joseki) since a toroidal board has only "middle" space.
That player will play alone, aiming to achieve a higher minimum score at the end of the game.
Other 2D variants can also be performed with edges joined in three other ways, resulting in a topological sphere, Klein bottle or real projective plane.
Another example is Margo, by Cameron Browne, a variant played with marbles that can be stacked on top of one another.
It has embedded 11 different boards, either three-dimensional shapes (including cube, sphere, cylinder, diamond, torus and Möbius strip) or flat fields with points connected to three, five or six neighboring points, but it's also possible to create custom boards.