Capture three to make an eye
Capturing three stones suffices to make an eye.
An example at the edge of the board.
When White captures at ...
...even when Black throws in with , White can make a second eye with
.
HugoDePayens? : Isn't the second eye a false one?
mgoetze: a is the first eye and b the second. They are both quite real I assure you. :)
This works away from the edge, too.
unkx80: What is implied in the capture three to make an eye rule is that if the stone exists, then the
stone must also exist before the rule is valid. Otherwise, White captures three stones and still ends up with a false eye...
RichardHunter: Readers of the British Go Journal will know that there are exceptions to "capturing three stones makes an eye".
Hans: If Black captures the three stones with , then...
... recaptures. Because of
and
the eye around a is a false eye.
A related page is capture two recapture one.
See also the pages in the Eyes Collection.
See also: