Gokyo Shumyo, Section 1, Problem 33 / Solution

Black lives  

B1 is tesuji. It is the effective use of the belly attachment suji. It deals with two problems simultaneously, namely White's cut at a and White's watari at b.

Main line  

W4 may be unexpected resistance. B5 makes miai of a and b.

Continuation 1  

After W5, the circled points show Black's liberties (four). Even if White effectively captures the stones, Black connects at a and White has three liberties : two inside the eye, and one internal, which Black cannot count. (See Richard Hunter's theory on Counting Liberties.)

Continuation 2  

After B2, White is caught in a shortage of liberties, so White cannot play at a.

Approach ko  

White's best resistance is this line, leading to two-move approach ko. (In practice, it may not be worth the effort because the line loses some territory points first.)

The following diagrams are just to prove the statement of the reference diagram, i.e. that B1 defends against two threats.

1. The cut  
2. The connection  

Caution! Black is not alive in sente! He has to answer. If not:

Beware of the belly  

White's belly attachment makes ko. Black cannot answer with B2 at W3, because W3 at B2 will then reduce him to one eye.

In the above diagrams, notice that Black answered White's attacks twice at the same point. White's strongest resistance is to play at that point herself (cf. the main line).

Now for some failures.

Wrong 1  

The vulgar (crude) move at B1 provokes a forcing magari at W2, giving White the time to play atari with W4.

Wrong 2 (at move 5)  

If Black hane at B5, W6 threatens to make two eyes, and W8 makes it ko.

Wrong 2 (at move 5)  

If Black turns at B5, White plays atari from the other side (again threatening to make two eyes) and then captures two stones with W8. Black can neither play at a nor at b, because of shortage of liberties.


Gokyo Shumyo, Section 1, Problem 33 / Solution last edited by hnishy on January 14, 2023 - 02:47
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