Costly atari

    Keywords: EndGame

Sometimes you need to play your kikashi while you can. But sometimes it is aji keshi or entails a direct loss. One common mistake is to atari a first-line hane when you are going to tenuki.

Here is an example from Rob van Zeijst's column in the [ext] Daily Yomiuri Online.

[Diagram]

Mutual Damage

[Diagram]

Mutual Damage (ii)

Giving two points komi, Black loses by one point.


But Black's atari at B5 in the first diagram is a mistake. Black can salvage jigo if he does not play atari.

[Diagram]

No atari

The difference is that Black has not sacrificed a stone in the top right corner. The extra point gives Black a tie.


What about White's earlier atari? Was it a mistake, too?

[Diagram]

Mutual Damage (B)

After B9 White has a dilemma. Maybe the best thing is to protect the corner.

[Diagram]

Mutual Damage (B2)

But after B2 White is plainly lost.


If White continues to mirror with W1:

[Diagram]

Mirror

W3 protects the corner. W7 is tesuji. If B8 captures at a, White plays at b.

[Diagram]

Seki

B2 makes seki. Now White suffers a big loss.

[Diagram]

Seki (ii)

White can try W1, but B8 is tesuji to kill White's corner stones.

[Diagram]

Ko

W1 is tesuji. B2 is a mistake. If Black prevents the seki, White makes a ko and wins.

[Diagram]

Seki (iii)


So White's early atari seems necessary to prepare for the atari with sente when Black cuts. Two similar ataris, one right, one wrong. Go is not a very easy game.

-- BillSpight


See also


This is a copy of the living page "Costly atari" at Sensei's Library.
(OC) 2009 the Authors, published under the OpenContent License V1.0.
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