Gokyo Shumyo, Section 1, Problem 13 / Solution

Authors:

Main line: Hashimoto Utaro 9p
Variations: Dieter Verhofstadt 1k, Bill Spight, tderz 3d EGF


[Diagram]

White lives

White has to start with W1.[1] There are many interesting variations.

[Diagram]

Main line

If Black tries to save his monkey jump marked stone. White throws in at W3 and creates shortage of liberties at a with W5. If Black resolves the shortage of liberties with B6, White plays W7, making miai of b and c.



We shall gradually investigate the alternatives back to W1.

[Diagram]

Variation 1

Depending on the situation on the upper side, Black can choose not to resolve the shortage of liberties, but instead play B6 here.

[Diagram]

Variation 1 (cont)

W3 captures four stones, and B4 throws in again at B2.

[Diagram]

Variation 1 (cont)

White connects, and gets one eye, and if Black makes the other one false with B3, White runs away with W4.[2] If Black is strong in the environment of W4, however, he can kill White, so one has to bear in mind that the status of the white group heavily depends on the upper side conditions. [this variant is elaborated in [#3] [3] )


[Diagram]

Variation 2

This is the variation in which Black permits his monkey jump to be cut off by playing B2; it results in seki. W3 is important. The rest of the moves are more or less forced. W8 and B9 complete the shape. White has all of her stones in one chain, so in order to capture them, Black has to play either a or b. In both cases a live "bent four" shape results. So Black will play neither of them, giving seki.

[Diagram]

Variation 2 (mistake at 3)

W3 in the above diagram is important for the shape created. If White carelessly plays descent at W3, Black kills at B4.

[Diagram]

Variation 2 (mistake at 3)

(10 recaptures at 8)

B4 here is probably even better for killing White.


[Diagram]

Variation 3

If Black answers W1 as here with B2, White doesn't make a fool of herself and she lives with W3 and W5. Playing W3 at B4, instead, would enable Black to make seki.


[Diagram]

Variation 4

If B2 at W3, W3 at B2 reverts to Variation 2. If B2 at B4, W3 at B2 reverts to Variation 1.
Of course, Black prefers this way of allowing White life.

[Diagram]

Variation 4a

xela: Isn't W1 a mistake? Black can kill this way?

[Diagram]

Variation 4b

[Diagram]

Variation 4a

unkx80: I think White lives this way. If B4 at W5, then White plays at a and lives by seki.

Thanks for pointing out this variation, this should have been in the solution.


[Diagram]

Wrong (10 at 7)

The points W1 and B2 are both vital points in this position and if White rushes to take one, Black takes the other. Here, throwing in as before with W7 doesn't work any more.


[Diagram]

Wrong (ii)

W1, B2, and it's all over.


[1]

This problem already appeared on rec.games.go resulting in an argument on whether seki is life or not. I hope we are not going to have that discussion here. So, White can live in seki, but that is not the main line given in the book.

[2]

There is an unwritten convention in life-and-death problems that to escape is to live.

[3]

碁経衆妙 Gokyō Shumyō, part 生之部 (life), problem # 13: [ext] tderz on godiscussions,
resp. entries #117 - 124: [ext] http://www.godiscussions.com/forum/showthread.php?t=234&page=3&highlight=shumyo


Problem 14
Back to Kanazawa Tesuji Series


This is a copy of the living page "Gokyo Shumyo, Section 1, Problem 13 / Solution" at Sensei's Library.
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