BQM 301

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[Diagram]

Kato Masao 9p vs Cho Chikun 9p

The most popular response for W1 is the shimari at a. However Black chose to play an iron pillar, presumably to protect the corner. My reasoning is that by playing at a, the stone will be too close to the strong (?) black wall. In other words, playing at a would lead to overconcentration which Black didn't want to.

Is my understanding of overconcentration and my reasoning for B2 correct?

Also, if you feel really helpful, could you give some reasonable continuations if White chooses to play at a or above? (presumably later, after White strengthen W1)

Thanks a lot

Agro1986 - 16k KGS


unkx80: I have no answer yet... but before any answer can be given, some simple reading or analysis is definitely required.

[Diagram]

Connection 1

Observe that there is a connect-and-die with W1 and W3 that connects the white+circle stones to the inside White stones. So the white+circle stones cannot be said to be weak for the moment.

[Diagram]

Connection 2

The second aspect is whether the bottom black+circle stones can connect to the corner. By looking at the sequence from B1 to W6 alone, the answer is no...

However, we see now that after W6, a Black move at a is an atari. We now look at a transposition of these moves.

[Diagram]

Connection 2

If B1 makes an exchange with W2, then B3 can now connect.

[Diagram]

Connection 2

White will never be happy to connect at W2. With the follow-up move at a, I don't think the black+circle stones can be said to be weak.

[Diagram]

Conclusion

Since the black+circle stones are not weak, I think Black is justified to play at B2, meaning that Black is not afraid of a White invasion at either a or b.

For example, if White a, then Black might look forward to a splitting attack at c.


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