Large Avalanche Turn Outward
After , the moves to are considered the best continuation, although there is some variation possible, especially for . After this, Black has to choose whether to save or sacrifice his three stones.
Nowadays, is considered the joseki move. Black allows White to take his three stones and the corner, making influence in return. accepts this exchange. The sequence to is the current joseki. In the past is was more common for white to play atari at instead of , followed by black a, white , 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.
If White does not accept the sacrifice, as seems to be more common nowadays, she jumps out at . If white answers 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.
With and , white tries to get some forcing moves in. Black may accept with at , but is once again more likely to go for a sacrifice with . After , the black group at the top is captured, but only in ko, and black has considerable counterplay, starting at . Note that a is black's sente, so the three white stones have little chance to move out.
White can also play atari at before the attachment at ( in diagram 4. After , the fighting obviously continues, but the position has not occurred often enough in professional games for me to discern a joseki.
Instead of pushing at a ( in diagram 3), black can also take the corner with this . White cuts with , and another fight ensues.
This used to be a popular joseki around 1950. Nowadays the fact that Black has to play two moves ( and ) to capture the corner is regarded too large a disadvantage.
seemed to improve on a black play at ( in the previous diagram), allowing Black to take the corner with one move, until the counter-measure of was discovered.
- @ a: next diagram
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 at a, White can create a ko, while if Black does not play , White plays at b and Black dies outright.
- Andre Engels
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