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March 2002's Go Answer of the Month

Dia 1 - Black to play.

Dia 1

A nice easy one this month. Black has one obvious eye. Where does he get his second from?

Try and do this on in your head rather than on a board...

The answer is that any second eye is going to come from capturing either the 1-4 point stone or the 2-2 point one. The harder part of the question is how to do this.

Dias 2 & 3 - The direct approach.

Dia 2   Dia 3
4 at 2.

The direct approach of 1 (or the equivalent of 1' at 2) fails. Although Black can capture the 1-4 point stone, White increases the sacrifice with 2 and when Black captures with 3 throws in with 4 at 2. If Black captured 4 with 5' he would only get a false eye.

So Black goes for the 2-2 point stone instead with 5 atari. White 6 relieves the atari and also prevents a direct black approach. 7, from the left is balked by 8 creating a shortage of liberties, so 9 approaches from the right and captures 4 as White captures 5 and 7. No second eye here.

If Black played 7' at 9, White again responds with 8, Black can capture with 9 at 11'. Now White captures 5 with 10 at 7' and although Black can capture another stone (6) at the 1-1 point, both the captured eyes are false.

Dia 4 - A dual purpose move?

Dia 4

So how about a move such as 1 here which threatens an atari at the 2-3 point and also threatens to make an eye with a play at the 1-5 point. It also guards the 1-1 point.

Unfortunately White just plays the sacrifice of 2 again and by 3 we are back to Dias 2 & 3.

If Black doesn't capture with 3, but ataris at the 2-3 point, White just captures at the 1-1 point and agin we revert to the previous set of moves - even if played in a different order.

Dia 5 - A round about approach?

Dia 5

So lets try starting as in Dia 2, but not capturing the sacrifice of two stones with 3'. If White connects with 4' at 5 then Black 5 can atari 4 white stones to gain a second eye.

However White just plays 4 at the 1-1 point and we revert to Dias 2 & 3 when 6 at 2 captures 5.

Dia 6 - The tesuji.

Dia 6

It turns out that the correct move is for Black to play the tesuji of 1 here immediately. Dia 6 shows one sequence that gains a second eye. If White plays 4' at 5 then Black gets a second eye in the corner by capturing at the 2-1 point.

If White plays 2' at, say, 3 here. Black can reply with 3' at the 1-3 point making miai of the 1-5 point and the corner capture. Other White 2's are similar.

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