Large Avalanche Turn Outward

  Difficulty: Expert   Keywords: Joseki
[Diagram]

The large avalanche: turn

After B1, the moves to W6 are considered the best continuation, although there is some variation possible, especially for W4. After this, Black has to choose whether to save or sacrifice his three stones.

Jonathan Cano: I've created a problem for a non-joseki variation on W4, at Large Avalanche Turn Outward Problem. The problem begins with W4 at B5.

[Diagram]

Sacrifice

Nowadays, B1 is considered the joseki move. Black allows White to take his three stones and the corner, making influence in return. W2 accepts this exchange. The sequence to 5 is the current joseki. In the past is was more common for white to play atari at B5 instead of W4, followed by black a, white W4, black b. After the joseki, black can exchange c for d to cut white off from the center, but black might prefer to force with e rather than c, and so keeps both in reserve until he knows which is best.

[Diagram]

White jumps out

If White does not accept the sacrifice, as seems to be more common nowadays, she jumps out at W1. If white answers B7 at a, black captures the corner stones at b. In this case white does not have an immediate forcing move on either side, so she usually prefers to move the fight to the top as shown in the next diagram.

[Diagram]

The continuation

With W1 and W3, white tries to get some forcing moves in. Black may accept with B4 at B8, but is once again more likely to go for a sacrifice with B4. After W7, the black group at the top is captured, but only in ko, and black has considerable counterplay, starting at B8. Note that a is black's sente, so the three white stones have little chance to move out.

[Diagram]

Ko

This is the ko that is left in the position. Alternatively, black can use the corner aji to force on either side.

[Diagram]

atari

White can also play atari at W1 before the attachment at W3. After W9, the fighting obviously continues, but the position has not occurred often enough in professional games for me to discern a joseki.

[Diagram]

The continuation

Instead of pushing at a, black can also take the corner with B1 here. White cuts with W2, and another fight ensues.

[Diagram]

Saving

Saving the black stones with B1, rather than sacrificing them with a play at W8, used to be joseki.

[Diagram]

Continuation

This used to be a popular joseki around 1950. Nowadays the fact that Black has to play two moves (B1 and B3) to capture the corner is regarded too large a disadvantage.

[Diagram]

Another possibility

B1 seemed to improve on a black play at W6, allowing Black to take the corner with one move, until the counter-measure of W4 was discovered.

[Diagram]

The continuation

This is considered good for White because Black still has to take the three stones off the board. So Black's territory is rather small, while White has been able to play on both sides. If Black plays B3 at a, White can create a ko, while if Black does not play B5, White plays at b and Black dies outright.

[Diagram]

A variation

If White plays W4 in the main diagram at W1 here, White can capture the three stones whatever happens. However, this gives Black too much thickness (note that Black a next makes a ponnuki in sente).


Authors:

  • Andre Engels
  • (add your name if you make a significant contribution to this page)

This is a copy of the living page "Large Avalanche Turn Outward" at Sensei's Library.
(OC) 2016 the Authors, published under the OpenContent License V1.0.
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