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June 2002's Go Answer of the Month

Dias 1a & 1b - Black to play.

Dia 1a   Dia 1b

Two problems from a Japanese magazine, neither are particularly hard if you are methodical.

Problem A

They key to this is to count the liberties now and determine how they will be after Black andafter White's reply.

There are two obvious Black moves, the two ataris. The 3-3 point atari fails since after white connects, white has 3 liberties to Black's 2. I'm not doing a diagram for this as you need to be able to metally visualise this.

The other atari, on the 2-4 point is more promising. It leaves the right black stones with 3 liberties and the corner white stones also with 3 liberties - so the question becomes can Black keep reducing White to 2 liberties?

Dia 2a - White wriggles, but never gains a liberty.

Dia 2a

This is a typical sequence. Black can keep white's liberties down. Black 3 is a key move which might easily be missed, White 3' at 4. Also Black 5' at 10 fails. Both are another exercise for the reader.

Problem B

Black is trying to kill white here. White has two weaknesses - the stone in pre-atari on the left and the fact that the lower string has no external liberties. Black on the other hand has two stones in pre-atari and in poor shape.

If White is permitted to atari the two stones - sente since the capture would be a second eye - he gets the time to finsh a second eye on the left. Black's correct move is just to remove his own weakness and White is left stumped.

Dia 2b - White can't make a second eye due to shortage of liberties.

Dia 2b

Black 3 is a common tesuji. Compare this with the killing sequence in the "J-group" in the corner.

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