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 white+circle (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 black+circle. 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 white+circle 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 white+square 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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