Nineteen point trick play

    Keywords: Joseki
[Diagram]
The trigger  

The extension at B5 here is the famous nineteen point trick play (also known as the "eighteen and a half point trick play"). Typical continuations for this joseki would be B5 at a or b: see 3-4 point low approach one-space low pincer press.

If White falls into this trick play, Black will give up nineteen points in the corner (hence the name "nineteen point trick play") but get a huge advantage anyway. Read on!



The trick play sequence

[Diagram]
Nineteen point trick play  

W3 and W5 are is taken in by the trick play. B6 before B2 is another way to lure White into it but her correct response is different.

[Diagram]
Continuation  

W5 is the real mistake in the whole sequence and should be played at W8. See below.

[Diagram]
Conclusion - W3 @ black+circle  

The sequence up to W9 results in a huge success for Black. White has 19 points in the corner, but Black has such a thick wall outside that its value is much bigger than White's corner. Besides, Black a is sente.


Refutations

[Diagram]
Descent  

Instead of W5 in the continuation diagram, White should play W1 here. While Black still gets a squeeze, White can take sente here.

[Diagram]
Don't cover  

In the conclusion diagram covering at a is not the best option. Rather White should turn at W3 and allow a capture two recapture one at a.

[Diagram]
Dodging early  

White can dodge this line of play with this calm variation. KataGo advises an even stronger resistance, turning at a and then pincering at b.

[Diagram]
Dodging early (2)  

In this variation, White dodges with a hanging connection, Black forces before connecting and W9 attacks the marked stone.


See also topic:1097 for more discussion on this trick play, as well as a tewari analysis of it. Another tewari analysis of this trick play can be found at Tewari Example 8.


Nineteen point trick play last edited by Dieter on October 8, 2021 - 00:27
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