BSR2003 B73 discussion

    Keywords: MiddleGame, Shape, Tactics

We are discussing this position:

[Diagram]

Position before B73

Dave: (...) Unfortunately I think that the 73/74 exchange (Black j, White k in the real game) creates some serious shortage of liberties problems for us black sheepers . I was hoping for the direct cut at a instead. Since the cut is still an important issue we can leave it for now but perhaps come back later to analyze how it would have gone.

dnerra: My intention was the following sequence:

[Diagram]

Now if White saves his stone at a, Black can still cut at b -- I think. If White instead protects against the cut, than Black a is very big.

[Diagram]

Faster way to play

Charles Oh, I assumed that Black was aiming at B1 here, which connects under, though with bad aji. (For example, White at a.)

Therefore I don't think White should answer B5 of dnerra's diagram - too slow.

 (Later)

I may have assumed that, but White at b prevents the connection.

[Diagram]

Black's bad aji

Dave It seems to me that White even has time to descend. If Black tries to cut...

[Diagram]

Black's bad aji

Dave What happens after White plays at a?


[Diagram]

Large-scale exchange?

Charles One line to assess after Dave's preferred immediate cut is this - exciting enough? It's a driving tesuji operation.

[Diagram]

Continuation

B1, W2 look inevitable. Now presumably B3 at a. But isn't White going to become thick in the centre?

[Diagram]

Who is better?

Dave White certainly is strengthened on the center right. But the aji is bad toward the top unless White adds a move. So who is better here?

Charles Black, unless White finds an aggressive continuation. The aji would be Black at a or at b. White could hope to deal with Black a by White c, Black d, White e. I'd hope White would play tenuki here and start trouble elsewhere.


[Diagram]

Failure with a different order

It seems more subtle to cut first with W4 and W6, but that fails (now Black at a, and White has no answer).

[Diagram]

Another way for White

Actually this way of pushing straight in is also interesting for White, if she wants to trade white+circle for the black+circle stones. After W8, B9 is the reasonable way to play; but now it is clear Black may get cut.

[Diagram]

Another way for White

Dave: The immediate cut leads to something like this because White's cutting stones have to give way with B5, because of a shortage of liberties. Now White has to consider how to protect the top without letting the center Black stones escape towards black+circle. This is a complex position for both sides, I think.

[Diagram]

Sample continuation

Charles Yes, all the toughest lines in this game occur in the variations. If W1 then Black makes progress into the top side and it is up to W9 to redress the balance in the game. So this looks to me less favourable for White than the driving line. But in a sense this is White playing more consistently, too. It's going to come down to what White can achieve in the upper right.


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