Small avalanche - trick play

Path: <= Trick Play
  Difficulty: Expert   Keywords: Joseki
[Diagram]
Trick play  

In the small avalanche joseki, B5 (instead of a) is a trick play that may be played when the ladder at b is good for Black. The refutation for White can be hard to find however.

[Diagram]
Tesuji  

W1 is natural to prevent the ladder, but after B2, it seems that White has a problem. The tesuji at W3 saves the day.

[Diagram]
Tesuji continuation  

With the moves up to W7, Black can cut off W1, but White takes the corner and manages to escape with W7 as well.

If White tries to avoid being sealed in by playing W3 at W5, Black will connect under at W3, and White's horrible shape quickly becomes apparent.

[Diagram]
Falling for the trick play  

With W3, White has fallen for the trick play. With the moves up to B8, Black seals white into the corner while cutting off W1. White can push through at a, but b is atari, forcing White to capture, after which Black can finish his wall with a move at c.

Update February 2023: As usual, AI has reevaluated this. The difference between this and the "tesuji" diagram above is small; either can be better depending on the rest of the board. White shouldn't play a, but can tenuki here: black's position looks more intimidating than the previous diagram, but white is a move ahead on the rest of the board.

Note also that W7 is a mistake: this move should be at d instead.

[Diagram]
Falling harder for the trick play  

W5 is even worse. After B6, the white groups are disconnected and heavy.

[Diagram]
A significant improvement for white over 'Falling for the trick play'?  

W3 is not so bad if white plays 5 as descent rather than atari.

Update February 2023: KataGo disagrees, and thinks this W5 is worse! See below.

[Diagram]
continuation  

As white descended she has an extra liberty and can push through and capture the stone on the 2nd line in sente, which is a big improvement over the previous diagram. I (Uberdude) think this is playable for white as she gets sente and there is still some aji on the outside: activating the marked cutting stone and the peep at a are things to look forward to.

Update February 2023: B1 is a mistake. Because the marked black stones have an extra liberty, the net starting with B1 at W2 is more effective

[Diagram]
KataGo's recommendation after white descends  

If white+circle were at a, then white could push out with W4 at b instead.

[Diagram]
Variation: why the extra liberty matters; B8 at black+circle  

Here, W1 doesn't work, because white has to fall back and play W5.


See also:


Path: <= Trick Play
Small avalanche - trick play last edited by xela on February 11, 2023 - 03:36
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