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Taisha five-way junction
  Difficulty: Expert   Keywords: Joseki

This occurs some way into the main variation of the taisha joseki and may even be a six- or seven-way junction. The point of this page is to sort out which variations are attested as pro plays, and which are presumed just trick plays. The latter are perpetuated by joseki books.

[Diagram]
Taisha complex line

For the hardcore enthusiast, this is position is the source of the major taisha variations. We'll look at Black a, less difficult than b or c.

Instead of the push of W10, the descent at d is also possible when there is a white pincer at the circled point (see the descent variations below).


[Diagram]
Normal

This is the expected development, after a while the groups in the centre make some shape.


[Diagram]
Reputable

Black 1 here has been played by some top players down the years (Shusai, Sekiyama Riichi, Hashimoto Utaro). The line continues with 2 and 3, and is thoroughly analysed in Ishida.


[Diagram]
An apparent impossibility

Black 1 here is a pro play, though perhaps not recently (any advance on Kubomatsu-Kitani in 1934?) This is a pushing battle with a trick play in it. Black 3 may look as if it's easy to refute - but beware the two-stone edge squeeze!


[Diagram]
Rare

This idea appeared in a couple of Go Seigen's games in the 1930s.


[Diagram]
Shuwa's move

Black 1 and 3, not mentioned in Ishida, were played by Shuwa.


[Diagram]
Unreasonable?

That leaves these plays a and b from Ishida unaccounted for; they may be outright tricks. Analysis is given there for a; for b too but that was played differently 1974-06-06 by Hashimoto Utaro against Magari Reiki (game on Gobase).

Gobase also has a game 1973-10-31 between 1 dan pros Inoue Hatsue and Kimura Yoshio in which Black tries c.

Sazn: A and B are Trick Plays

Charles Matthews



Descent Variations

[Diagram]
Taisha--Descent Variation

SnotNose: Instead of the push at a White plays the descent W10. As far as I can tell, W10 (rather than a) is played only with a white pincer in place (WC). (What motivates the decision to play W10 vs. a in such cases? I do not know yet.) At least three non-trick-move continuations have been worked out, two beginning with Black b, the other with c. I do not (yet) fully appreciate the relative merits of these continuations. Only two continuations are fully shown below due to limitations of my memory (I'll update when my memory is restored).


[Diagram]
Taisha--Descent Variation, Continuation 1

Continuation 1. Black has sente, but his center stones are heavy. A Black play in the direction of a might be urgent. This continuation appears in WholeBoardThinkingInJoseki, as does another that includes a White atari at B9 rather than W8. Unfortunately, I cannot remember this other variation right now.


[Diagram]
Taisha--Descent Variation, Ccontinuation 2

Continuation 2. Black finishes with a and achieves a much lighter shape than in continuation 1 above. At the same time, White has less definitive eye shape on the outside. The cost of these advantages for Black is a loss of some corner territory. Perhaps this makes continuation 2 the better choice, in general. A continuation very similar to this appears in IshidasJosekiDictionary but with little commentary.


Another non-internet source for ideas involving the descent varation include NieWeipingOnGo (at least one game in that book uses this variation).



This is a copy of the living page "Taisha five-way junction" at Sensei's Library.
(OC) 2003 the Authors, published under the OpenContent License V1.0.