TrumpetConnectionShapeProblem/Joseki discussion

tderz It makes sense to explain the order of moves with a real example. Here is a sequence how this shape occurs frequently in games:

[Diagram]

A common 4-4 joseki



Black wants to make White overconcentrated on the right side, e.g. there might be a small white wall WC (too) nearby.
(Only) In that case it does not matter if White is made even stronger by the black sacrifice - and - any chance of attacking White - is lost.
Of course White might try and resist otherwise.

[Diagram]

The continuation (1)

Of course, White must capture the black stone BC. However, before doing that he still can play two useful kikashi - and - only in the right order. Kikashi is all about timing. This is an easy problem and kikashi/timing problems belong to the most difficult problems in Go.

[Diagram]

the continuation (2)



W1 after the W3-B4 exchange would not work, because W2 (at B2) would not be atari anymore.
The WC wall is now much too close to W5, W7.

[Diagram]

The continuation (3)



That this is not only an academic exercise is shown by the aji around a, after which White could threaten to put the WS stone in motion (life) or - after Black defends around b, do something else useful with the stones around a.

Charles See also attach-crosscut corner patterns. I wouldn't call the crosscut a real 'joseki': it is an example of a contextual sequence.


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