# Gokyo Shumyo, Section 1, Problem 26 / Solution

White lives
Main line

The tesuji here is . After , Black can't create a dead shape with a, because he is in shortage of liberties (this is oshitsubushi). Note what a difference a black stone on the marked point would make.

Variation 1

White has to be careful to answer at and not at . The strength of is precisely that it already prevents the connection underneath.

Variation 2

Answering at is the only move. It appears as if White can destroy the eye after this sequence by throwing in again at , but White will simply connect at a.

Variation 3

Just to clarify: If Black tries to leave White with a big eye by connecting at a (almost filling the enclosed space with the dead shape of three in a line), White runs to b and claims a second eye at c.

How should White then respond if Black tries playing at d? That won't work for Black; White runs along the second line and if Black follows, eventually White can block on the first line and the resulting capture will give the second eye (at least). I don't think playing at e directly will work; seems like Black sets up a ko that way. White could probably also escape in this sort of situation. -- KarlKnechtel

Variation 3

There are many ways for White to go wrong. Let's assume she takes as the obvious move, but fails to see the tesuji of in the main line.

Wrong 1

Black's hane produces a ko

Wrong 2

Black kills with the same hane.

Wrong 2 (variation by KarlKnechtel - there are some other similar ways too)

White lives?

After , can white live?

xela: Yes, I think at a works.

White lives

Why not the simple descent of ? This makes miai of a and b, no?

xela: Black won't be kind enough to reply at , but will play c instead.

Gokyo Shumyo, Section 1, Problem 26 / Solution last edited by xela on December 10, 2008 - 06:28