Xuanxuan Qijing Problem 198 / Attempts

Table of diagrams
Threat to connect under, then cut
Wrong atari
Another cut
Double damezumari
Double snapback (W13 @ WW)
Best response by Black
Refutation
White dies
Bass's attempt: sente eye on the left

[Diagram]

Threat to connect under, then cut

White threatens to connect under with W1. If black prevents this with B2, white cuts with W3. Now black has two ways to give atari.

[Diagram]

Wrong atari

If B4 gives atari from this side, W5 guarantees that white will cut one way or the other. So black should atari the other way.

[Diagram]

Another cut

After B4, white cuts yet again with W5. Again, black has two ways to atari

[Diagram]

Double damezumari

This atari doesn't work, because after W9, black is caught in double damezumari

[Diagram]

Double snapback (W13 @ white+circle)

So black tries the other way. But after W13 at white+circle, it is a double snapback

[Diagram]

Best response by Black

The best response by Black is simply to fix the problem in his lower center group. W3 makes one and a half eyes, B4 captures the lower right corner, and then W5 makes two eyes by oshi-tsubushi.


[Diagram]

Refutation

Bass: If white starts at W1, then black can answer at B2 to remove the eye on the left. White will naturally play the snapback sequence.

[Diagram]

White dies

Bass: Capturing the four stones is gote, so white cannot get two eyes.

If white plays W1 at W3, then B2 at W1 still kills.

[Diagram]

Bass's attempt: sente eye on the left

Bass: White can secure the eye on the left in sente, so now the single eye gained by the snapback sequence will be enough.


This is a copy of the living page "Xuanxuan Qijing Problem 198 / Attempts" at Sensei's Library.
(OC) 2014 the Authors, published under the OpenContent License V1.0.
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