2torial #0589:
Learn2 Play Go (continued)

Avoiding suicide

Since a stone must have liberties to be viable on the board, if you deliberately place a stone where it has no liberties, you're committing suicide, which is illegal. There is, of course, an exception to the rule.

If, by placing your stone in a suicide position, you capture your enemy's stones and thereby create a liberty for your own stone, you're allowed the move. This is demonstrated in the picture below, where black covers the point marked by the star in diagram A. This may appear to be illegal, because black will then be surrounded by white, but because black can capture the white stones and create liberties (marked by stars in diagram B), the move is successful.

This particular kind of liberty, protected by the group in diagram B, is called an eye, and is very handy to have in go. Eyes provide you with liberties that your opponent usually can't play into, because to do so would lead to capture.

But it takes a particular kind of eye to be foolproof, as we'll see in the next step.