Endgame Problem 3 / Solution

Sub-page of EndgameProblem3
[Diagram]

Solid connection

B1 saves the black+circle stones. If Ba instead, W1 may lead to their capture.

[Diagram]

Seki

And now W2 makes a seki. Black can play a ko but with the risk of losing everything. Hans



Miai Value analysis

[Diagram]

Seki

Let's take this as the zero diagram.

[Diagram]

After B3, A and B are miai for Black, so he lives with 7 points. C-D is still Black's sente.

[Diagram]

Instead of playing the seki, White can also execute W2-B3 in sente. Later, Black's block will be sente, so we count this as 4 points (5 for Black and 1 White at D).

So this W2 is a sente with value 3, while making the seki is a gote move with miai value 3.5 and therefore better in most circumstances.

[Diagram]

White first

White can kill the whole group this way

[Diagram]

White first

Or this way via bent four in the corner

[Diagram]

White first

This might be the strongest resistance: ko.

[Diagram]

Just the stones

White can also take 8 stones in sente (the follow up would be larger).



If White takes the sente rather than the ko, we get the following game tree

                     -6.25 (9.75)
                    /       \
               3.5 (3.5)   -16 (0|21))
                  / \       / \
                 7   0    -16 (-37)

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