Noseki - 4-4, low approach, attach on top, peep

   
[Diagram]
Normal joseki  

When black attaches on top with B2, white normally plays hane at W3. This page discusses what happens if white instead peeps with W5 immediately.

Peeping first is not joseki, and is locally bad. Only under special circumstances is this move playable, see: Pro play example

[Diagram]
What white is afraid of  

The peep might seem attractive when white is afraid of B4 at a (taking the corner) or b (a sacrifice to potentially overconcentrate white)

[Diagram]
Options  

For black, the normal response to W3 is B4. White can next try several moves, like the hane at a, the extension to b and c, or the jump to d

[Diagram]
hane  

After the hane of W1, black can cut at B2, and sacrifice two stones. With B6, black gets influence in the center, after which black forces white to capture the two sacrifice stones with B8 and B10 (white captures at a).

[Diagram]
extend  

Simply extending to W1 is slow and unappealing. Black takes the corner with B2, and white is forced to make a base for his heavy group with W3. White is clearly worse of than in the normal joseki

[Diagram]
jump, block  

If white tries to play lighter with W1, black can still block in the corner. White then makes shape with W3, but his position is cramped.

[Diagram]
jump, peep  

Black might also try the peep B2 if influence is more important. Now, white will have to deal with the risk of black pushing through and cutting. W3 is one option. White's position is low, and black can still take the corner with B4 (which can also be elsewhere)

[Diagram]
corner  

If white plays W1 like this, black will hane. If white plays counter hane with W3 at B4, black will get to play hane at the head of three on both sides. So white will probably extend, allowing black to take the corner.


Example from professional play

[Diagram]
Yi Se-tol (W) vs. Rin Kaiho (B) in 2002  

Here, white chooses W2 due to the special circumstances of the position of the white+circle marked stones.


Noseki - 4-4, low approach, attach on top, peep last edited by 82.210.116.71 on November 12, 2009 - 18:41
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