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February 1998's Go Answer of the Month

Dia 1 - The lumberjack's rectangle.

Dia 1

In a recent tournament, a West Surrey club member arrived at this corner position. It is slightly bigger than a "Carpenter's Square" and was named the "Lumberjack's Rectangle" by Reading Go Club.

Dia 2 - Naïve?

Dia 2

This shows the "tidy" set of moves. Is it naïve of White to expect this?.

Dia 3 - Disaster!

Dia 3 6 at triangle

This shows what could happen with an aggressive Black and a trepid (?) White. Disaster for White.

What should happen here? Can White handle an aggressive Black - if so how?

Dia 4 - What happened in the game.

Dia 4

Which lets White live easily. Black can cause more havoc than this.

Having investigated this in the past month, I have concluded that this problem is non-trivial and that I am unable to provide a full answer this month. I will present my findings so far - they may be incorrect, feel free to let me know any errors - and I'll come back to this problem in a few months time.

Let us start investiagting the hane on the long side. Diagram 3 showed what can go wrong if answered recklessly.

Dia 5 & 6 - A better reply?

Dia 5   Dia 6 14 at triangle.

Some dan players suggested that rather than capturing Black 1 directly, running along the first line might help. In this example here, it appears to - the result is a seki.
But ...

Dia 7 - Black has a more powerful play.

Dia 7

Black 7 is strong.
In this particular sequence, White cannot atari the Black stones, whilst Black can capture the 3 White stones on the edge and connect out. This kills White.
Assorted variations on White 8 et al exist, all leave White dead.
I conclude that answering the hane like this is bad for White.

Dia 8 - White needs to answer the hane elsewhere.

Dia 8

Answering at the 2-3 point seems a better move. Here White lives with one eye at triangle and one from capturing either 5 or 7.
So far every Black attempt to kill after this White 2 has failed.

I also think that White 2 at the 2-2 point works - not yet fully investigated.

Dia 9, 10, 11, 12 & 13 - White 4 answers to assorted Black 3s.

These five diagrams show moves which have been confirmed by GoTools as leaving White alive. They may not be optimal, but they do work.

Dia 9   Dia 10   Dia 11   Dia 12   Dia 13

I may come back and add a diagram or two to this "long side hane" page later.
I will address other Black attacks including the short side hane and the 2-2 point in future months.

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British Go Association
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