Attachment on the second line

    Keywords: MiddleGame, Joseki

This page is in need of attention.


Once Black attaches at B1, two common responses for White are a and b.

[Diagram]
White wants thickness  

W2 is a solid line of play. Black gets additional territory and White gets solidity facing the right hand side.



This works well for White when White has stones to the right at a or b. White stones closer than that would yield an overconcentrated shape.

Alex Weldon: If the White stone is much closer (say at c, especially if the ladder towards the upper right is good), or if Black is playing this too early in the game, and White is willing to play lightly, it may be possible to omit W4. This would make the sequence gote for Black.

[Diagram]
White wants territory  

If White chooses to capture B1 with the hane at W2, B3 forces White to play W4 to complete the capture of B1.



Black will then roll over top of White with B5. Black obtains outside thickness, while White gains some territory. For White to resist B5 by playing W4 there herself is inconsistent with W2.

Velobici: Such is this 10k's understanding. Please correct my errors and enrich this page.

Charles I saw a 4 dan and a 7 dan discuss this, last year. The 4 dan said he'd automatically play W2 above; the 7 dan commented that the 4 dan needed to change his entire attitude to the game. So, who am I to comment?

Actually, this is one of the most basic middlegame joseki. Even so, you have to look at crawl lines to understand the local tactics.

[Diagram]
Crawl  

Here W1 is natural resistance.



Black has several choices: at a, at b and possibly some ways to fight out with black+square.

[Diagram]
Continuation  

If Black avoids complications, up to B5 is expected.



Clearly here White has played in a territorial way, and Black has gained in influence.


Bill: So far, this is one of those discussions that does not take the context into account. (However, see below.) Often this attachment is a sabaki or shinogi play; it may also be a good yose. This second line attachment would be bad on an otherwise empty board.

[Diagram]
Low  

Bill: For instance, through W6 Black is too low.

[Diagram]
Also low  



[Diagram]
Not in Gobase  

Bill: I did a little database searching on GoBase, and no instances of this pattern showed up. You have to have other stones in the vicinty for the pros to play B1.


[Diagram]
Defense  

Bill: The database guys can check this out, but one of the commonest situations where this attachment occurs is as a defense when white+circle separates the two Black stones.

[Diagram]
Kikashi  

Bill: Another common use for this play is as kikashi against Black's corner enclosure. The clamp at W3 also occurs frequently in other contexts, especially where White wants to play lightly.

[Diagram]
Endgame move  

unkx80: This second line attachment is also commonly seen when there is a white+circle one-space jump stone, and can be a very big early endgame move.

[Diagram]
Endgame move  

unkx80: If W2 gives in, then B3 gains a substantial amount of territory. Later, Black can aim for a or b, which may cause W4 to immediately patch up this weakness, allowing Black to gain sente.

[Diagram]
Endgame move  

unkx80: If W2 resists, then B5 and B7 can push into White's territory on the right. Whether Black's sacrifice of B1 is properly compensated by the breaking in by B5 and B7 depends on the wider context.




This contact play technique is particularly useful for making shape for cramped groups on the side. It is quite common to reinforce the two-space extension.

[Diagram]
Moves 78 to 87  

In reply to black+circle, W1 builds strength. White is defending, but now there is a chance of White a to cut in the centre. (From An Younggil-Ch'oe Myeong-hun (B) 2001-06-07.)

[Diagram]
Moves 88 to 97  

Again White plays contact with W5. This time Black answers solidly with B6, to keep up the attack.

[Diagram]
Moves 98 to 107  

In the end B10 strengthens the centre. Here attack and defence are well balanced.


Further examples:


Attachment on the second line last edited by tapir on June 25, 2008 - 14:00
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