Gokyo Shumyo, Section 6, Problem 1 / Attempts

 Table of contentsAttempt 1 Attempt 2 Attempt 3 as Solution 1

Attempt 1

Black to play and connect underneath

This move stands out to me because 'a' does not add any liberties to the white group.

Black to play and connect underneath

The atari at 9 allows B to cut off 8. Playing 6 at 10 allows 7 at 6, cutting off the white stones as well.

Black to play and connect underneath

The atari at 'a' again forces white to connect at the marked stone, allowing black 'b' to kill off the white cutting stone.

Black to play and connect underneath

3 @ the marked black stone. Playing 1 on the other side still fails, as W cannot bridge under due to a connect-and-die.

Let's examine other responses.

Black to play and connect underneath

This permutation reverts to above.

Black to play and connect underneath

Easy variation for 6: a and b are miai to save 1 and sever the chain of W stones connected to 4. The continuations are given:

Black to play and connect underneath

4 at the marked spot; W's cutting stones are in a hopeless. situation.

Black to play and connect underneath

B has 7 liberties, W is trapped and has only 4.

Black to play and connect underneath

Little more complicated variation for 6. Pushing with 9 is key; if W plays a instead of blocking at 10, B connects underneath with 11 at 10.

Black to play and connect underneath

If W insists on cutting B off by playing through 4, B returns the favor at 5, triggering a race. However, W only has 3 liberties to B's 5 or more. W cannot escape. 2 at 4 leads to 3 at 'a', postponing the inevitable.

Black to play and connect underneath

unkx80: I am not sure about your claim that Black has at least 5 liberties. It seems to me that and causes Black to have only 2 liberties.

Black to play and connect underneath

After B at 'a', W at 'b', B at 'c', d and e are miai to trigger the capturing race, reverting to previous diagrams.

Black to play and connect underneath

This placement of 6 seems complicated. See continuation...

Black to play and connect underneath

B sacrifices the marked stones to prevent W connecting at 'a'. If W connects at a, B at b is atari and W's position collapses.

Black to play and connect underneath

5 at the marked spot. Instead, W saves his stones, but allows B to bridge under.

Black to play and connect underneath

On second thought, seems like B@1 fails?

Attempt 2

Black to play and connect underneath

Perhaps the move at 'a' is too early. Let's try at 1.

Black to play and connect underneath

If W hanes to the right, a and b are miai to cut off at least 1 white stone, ensuring the connection

Black to play and connect underneath

If W hanes to the left, 3 and the response at 4 play out slightly differently; now a and b are miai for black to cut, and b and c are miai for black to save the cutting stones. W's only hope is to play b.

Black to play and connect underneath

Unfortunately, after 4, W's marked group is in atari and cannot escape.

Black to play and connect underneath

If 4 here, this sequence follows. @ a, @ marked stone, @ b, cutting off . I believe the 7-8 exchange can be omitted, but I don't see why B would do that.

Black to play and connect underneath

4, 6 here reverts to the above

Black to play and connect underneath

@ a, @ b, @ c. White's stones have been cut off and are hopeless.

Attempt 3 as Solution 1

elvard: I've found this as solution. Idea is already in previous attempts, just everytime there is one or more unnecessary moves.

Black to play and connect underneath

is the solution. It's sort of asking move, waiting for white's response at 'a' or 'b' and then deciding the proper connect underneath technique. NOTE: Exchange of Black 'c' for White 'd' is not required since it doesn't add or take a liberty of white group.

White defends at '1'

The draw back at is essential as it prepares for 'a' followed by white connect at 'b' which tooks him off one liberty.

Black is connected

White can't block at 'a' since black will play atari at 'b'.

White try other way

If white try , connect. White can't stop this connection.

White try to cut

White is catched in "ladder". Soon or later will run out of liberties and will have to play 'a' or capture stone at 'b'.

Gokyo Shumyo, Section 6, Problem 1 / Attempts last edited by gnostic on January 27, 2014 - 13:51