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May 2003's Go Answer of the Month


Dia 1 - Black to refute all the wrong White moves.

Dia 1

This problem derives from the "White to kill" problem for this shape in Slate and Shell's Intermediate Life and Death by Maeda Nobuaki.

As part of this problem, you'll have to answer that problem too, but here I am interested in how Black refutes the 12 of 13 possible White attacks that are wrong. 7 on top line, then 4 then 1 then 1.

Some of the 12 are trivial, but two or three get complicated.


Let's start by getting the correct White play out of the way. It is the hane on the top line which is typically answered either by a hanging (top line) or a direct connection or . The first becomes the "J group" the second becomes one of the "L+1" groups. Both are killable.

Dias 2 & 3 - The correct white attack.

Dia 2   Dia 3

Note that as the problem was shown, White would have problems in Dia 3 if he played 3' at 6 with Black trying to escape to the left, the 2-2 point is better here.


Next to some of the more troublesome incorrect White attacks...

Dia 4 - White tries the "J Group" attack straight away.

Dia 4 10 at 1.

Black lives in seki.

4 must be used to widen the eyespace. If 4' is played at 9' for "shape", then White 5' at 4 reverts to Dia 2.

6' must not capture at 8, else White plays 7' at 12 and Black runs out of liberties very soon.

Dia 5 - The 2-2 point.

Dia 5

Black lives in seki. Note that a White descent to the edge on the right is sente and a good ko threat. Whilst extending from 7 to the 5-1 point is not, since Black captures and White has to recapture giving Black a free move.

White could also play 3' at the 2-1 point...


And now for one typical of the simpler points to refute. In the next diagram I have shown a Black response that lives - it may not be optimum and it does lose the two second line stones, but the main group lives.

Dia 6 - A 2-1 point.

Dia 6

The other attacks are straight-forward for Black to handle. I don't plan to put diagrams up, but if anyone has difficulty with a particular variant, let me know and I'll contemplate posting an update here.


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Last updated 2004-08-10
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