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TFG9 White At The Top
Keywords: Life & Death
Remember, here we are concentrating on the situation of the White group in the center top, ignoring for the moment the state of the black stones to the left.
(White 2,4,6 elsewhere)
As noted elsewhere, if Black plays first, White has four liberties. This means that if Black could make four liberties on the left in sente, he could start here and capture White - in theory.
What it really means is that if Black makes five liberties on the left, White can't afford to continue there and is forced to come back to the center top and play there. What happens if she does?
If White tries 5 here, extending the liberties of the cutting stone, B stops White cold with 6, reducing her to two liberties (either of the points a next puts White in atari).
From this it is clear that White 1 above does not help White. What next?
Note that this case raises the important question of what happens if both sides live. Assuming that White came back to the center after not being able to capture Black on the left, who wins the game if Black lives on the left while White lives in the center? But is this the best that Black can do?
(2 elsewhere) The count is B + 2, W - 1 = Net +1
(2, 4 elsewhere) The count is B + 3, W -1 = Net +2 with +1 in the previous diagram so total Net +3
(2, 4 elsewhere) Final count is +3 here with +3 in the previous diagrams for a total of six internal plays required for Black to capture White.
Note that Black can't switch 4 in diagram 2b to here. Because White has an outside liberty at a, she can throw in at 5 and after Black captures at 6, trap two black stones with 7.
So at this point White has only one eye at the top but has expanded from four liberties to eight liberties in gote, i.e. if Black plays next on the left; or seven in sente (if Black plays next at the top and lets White play next on the left). What does this mean for the status of the black stones on the left? Remember that White played tenuki on the left in order to play at the top.
This is a copy of the living page "TFG9 White At The Top" at Sensei's Library. (C) the Authors, published under the OpenContent License V1.0. |