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ParallelLadder

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Ladder
ConnectingWithKeima
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NetSolution10

 

parallel ladders
  Difficulty: Beginner   Keywords: Tesuji, Tactics

[Diagram]
Choosing a good ladder

Here White has a choice of parallel ladders.



Because BC breaks just one of them, White must be careful. W3 and W5 are the correct way.[1] Now Black's stones can't escape.

[Diagram]
Mistake

W3 here is a mistake, from the point of view of capturing Black.


[Diagram]
The ladder fails

Later on in the ladder B2 makes it impossible for White to continue.



Bearing driving in mind

[Diagram]
Choosing a good ladder

Moving BC closer along the diagonal does change things, White might then want to play W1, W3 and W5 here instead: a driving tesuji.[2] It all depends on the direction of play whether capturing Black on the left, or blighting BC on the right, is bigger.

Charles Matthews



[2]

[Diagram]
Choosing a good net

Calling either ladder correct is questionable, when the net at W3 also captures Black's stones. If Black tries to escape, say with B4, White can play atari. Note that the net works even if there is a black stone on the circled point. -- Bill


[Diagram]
Netbuster

Charles OK then, perhaps the final version of the lesson needs an extra stone, such as BS.


[Diagram]
Check the knight's move net

It is painfully easy to miss a knight's move net like W3 in a real game (W3 at a fails much more obviously). Up to B10 Black looks to be well set to escape.


[Diagram]
Check the knight's move net (continuation)

Urgh - the paper is too small to contain the rest of the sequence ... Black at a is about to be strong.

A better version of the original diagram would therefore deprive WC of further liberties.



This is a copy of the living page "parallel ladders" at Sensei's Library.
(OC) 2003 the Authors, published under the OpenContent License V1.0.