Illegal Moves in Go — Suicide, Ko, Superko | PlayGo.gg

A move is illegal if it is placed with no liberties and isn't capturing anything.

What is an illegal move

An illegal move is any play forbidden by the rules of Go. Three families cover almost every case:

- Self-Capture: placing a stone where it would have zero liberties and it does not capture any opposing stones. - Ko: A repeating situation where both players can keep capturing each other. To stop this from going on forever, one side needs to play elsewhere before taking the 'ko' back. - Off-the-board: placing a stone on an occupied intersection or outside the playable grid. Pass is a separate, legal action.

When does the rule actually matter

In real games, illegal moves are rare. For now, just try to remember that you can't place a move down that has 0 liberties. This should cover most cases! Online clients such as playgo.gg silently reject illegal moves, so you won't have to worry about making them!

Example of an illegal move in a game

There aren't any illegal move examples from a real game because... they are illegal! If you want to solidify your understanding on this, please navigate to the tutorial section on illegal moves! You can try it here.

Illegal moves are usually never played, unless its over the board by beginners — online, the system catches your mistake and does not allow the move to go through.