Joseki-related life-and-death example 1
Joseki
can also be played at a. In fact, it is the most common reply in professional games.
can also be played at b.
ends the joseki.
Discussion I
The group in the corner is alive, as discussed in L+2 group.
However, a Black descent at a is a threat to the White group.
The atari at
is a mistake. After
, white is caught in a shortage of liberties and is unable to play at a.
Discussion II
Diagram 1: In this diagram, White is alive too. (See J+1 group.)
However, the descent at a threatens to kill unconditionally. [1]
The throw-in at
followed by the placement at
is the tesuji. After which, a and b are miai, while c and d are also miai. White dies in a bent four in the corner dead shape.
Author:
[1] Note however that it is usually an endgame mistake to play the descent. Instead, Black should start at b.
Bildstein: That's very interesting. Can anyone explain why?
tderz: White will have about 5-6 points. (depending on the timing of the n-m-p exchange).
Black ends in sente.
tderz: White will have about 4-1=3 points or less (depending on the timing of the n-m-p exchange).
Black ends in gote.
Conclusion: starting with b in dia.[1] seems to be about 2 points better for Black, and it seems to me that Black is relatively free to chose when to play, because White has no sente variation herself for improvement.
I hope that no errors crept in.
![[Diagram]](../../diagrams/30/139829c0d66dcb5c1b761536145c4dc0.png)
![[Diagram]](../../diagrams/8/7b1b56cddd0486794eced70c0e450b2c.png)
![[Diagram]](../../diagrams/32/917d92693277570cc4b4432b1b6fae0a.png)
![[Diagram]](../../diagrams/9/f0ab97ba8990bd688ef3767847802e56.png)
.
![[Diagram]](../../diagrams/0/5c2569ee3c993141731e052046d62594.png)
![[Diagram]](../../diagrams/34/68e0e9b533ddb84df051a9ba3e6d430b.png)
![[Diagram]](../../diagrams/44/e23c98fc078d1ac79dbfbc5d3917444a.png)
![[Diagram]](../../diagrams/33/ec8fead25aed6bb67078be0b439e0e0f.png)
![[Diagram]](../../diagrams/41/66a32f8bb5d707b660cf4aa3c8520695.png)
2024 the Authors,
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