Main line: Hashimoto Utaro
Variations: Dieter
If at
here, cutting at
makes miai of a and b. Note that if White sacrifices just one stone (
at c), it's a ko after
at a. :
If here, capturing three stones with
assures a quiet life. Even if Black throws in at
, White is alive with a and b being miai.
at
. The variation is long, but up until
in this diagram it is forced and the
-
exchange is well known. White has to find the throw-in at
, though.
We will have a look at some preparatory moves: why White should not yet start the well-known sequence.
If a has not yet been exchanged for b, White runs out of options. Whatever she does, Black will connect at c.
Blocking here is not sente: Black can take time to hane. White can't makes an eye in the corner because a and b are miai for Black.
If at b then
at a and there are only false eyes in the corner.