Xuanxuan Qijing Problem 297 / Attempts



Solution

[Diagram]

Solution

Black can't save black+circle.

(Later) Actually a ko with B1 at r




Failure

[Diagram]

(W8 at B1)

[Diagram]

[Diagram]

[Diagram]

B1 is a double threat ladder-maker but W2 is a double ladder breaker.

[Diagram]

(B1 can also be at other marked spot)

[Diagram]

[Diagram]

For other B1, White just starts taking away Black's liberties.


[Diagram]

unkx80: I never seen this W2 before. But I think after B9, Black can get at least a ko. Can Black do better?

char: I can't find anything better than a ko.

[Diagram]

unkx80: Actually, this W2 is the main line. I think the whole main line solution is about 30 moves long; how many amateurs can read this long without using a go board as an aid?

char: Let's open the can of variations =)




Double Threat

[Diagram]


Ladder 1

[Diagram]

(W10 at B3)


Ladder 2

[Diagram]



Double Ladder Breaker

XuanxuanQijingProblem297/Attempts#toc7 XuanxuanQijingProblem297/Attempts#toc8 XuanxuanQijingProblem297/Attempts#toc9
[Diagram]

Since the two ladders are parallel, theoretically any white stone between them breaks both ladder.

However, playing a white stone at d or further doesn't work (the diagram on the right).


Double Ladder Breaker 'a'

[Diagram]

Double threat, again.

B3 is not the only move; there are several other working moves.

[Diagram]

[Diagram]


Double Ladder Breaker 'b'

[Diagram]

W10 at B3

[Diagram]

After B17, there are two ladders, starting with x and y.

[Diagram]

White can once again try to break both ladder by playing at W18 or r, but it won't work.

[Diagram]

[Diagram]

(W36 at black+circle)


Double Ladder Breaker 'c'

[Diagram]

???


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