3-4 point, high approach, inside contact, solid connection

    Keywords: Joseki, Tactics

Table of contents

Joseki

[Diagram]
Joseki  

The canonical joseki for the solid connection at W4 is as shown, with W6 making a three-space extension from a pillar? of two stones, completing the joseki. Here the low extension is shown, W6 may also be played at the high extension at a. The low extension emphasizes territory, while the high extension emphasizes influence. See fourth line vs. third line for more discussion on this aspect. The "White extension" section below discusses some aspects of these extensions.

Depending on the left side, B5 may also be played at b or c, each with its pros and cons. The advantage of B5 here is that it finishes the position in one move. See the "Black extension" section below for more.

In older days, B5 at d is also seen (Takahashi Shigeyuki (B) vs. Go Seigen 1936-04-14), but presently it is no longer considered to be joseki. See 3-4 point, high approach, inside contact / discussion about why d is considered to be too wide.

In special cases, B5 may also be played as a pincer at or around W6. See the section on "Black pincer variant" below for more.


White extension

[Diagram]
Low extension  

With a checking extension at black+circle, it is possible for Black to invade this three-space extension if White does not defend at a. Usually the result of this invasion is that Black connects back with black+circle, while White has a wall. However, this wall is without base, so depending on the remainder of the board, the White group might actually become a floating group.

[Diagram]
Low extension  

The resistance at W2 is rarely good. After B3 and B5, a and b are miai for connection so the invading Black stones are in no danger. On the other hand, White is left with many cutting points.

[Diagram]
High extension  

After the solid connection (circled) and the high extension (squared), Black can invade.

[Diagram]
Invasion  

B9 makes miai of a and b. Alternatives are B5 at B9 immediately and W8 at a for ko.

In particular if Black has support at the circled points, this invasion can be devastating.

dnerra: Hmm, it looks to me like White has many other options, and the chosen one is far from optimal. There are more choices, but W6 looks like a mistake unless White really really has to protect territory in the upper right.

When I have seen B1/W2, B3 was played at c (cf. 'deep invasion' dia.[10] below), making miai of b and d. Far more frequent than B1 seems to be c directly however:

[Diagram]
High extension  

tderz B1 is not as optimal as c (see [10] below), because a black move around e is missing.
IMO, there is nothing wrong with a little running fight , starting with W2.
If now black f, white g, then a partial result will be that the area around e will be influenced more by White and Black's influence around p will be reduced.

If B goes for another option, starting with sabaki tactics k-l-m or so, it's just a different game. Important is simply that one is not too obsessed by the idea The area around B1 must always be White's area, rather stay flexible and be ready to exchange. tderz

[Diagram]
[10] Deep Invasion  

B1 is very effective. It threatens to link up at a. If White prevents this with W2, the fight can become very difficult for White after B3. Often, White just defends with W2 at b. After that, Black can treat B1 as kikashi if he likes.


Black extension

[Diagram]
Joseki  

We now discuss the extension of B5, and its two variants a and b.

[Diagram]
One space jump  

The one-space jump of black+circle finishes the joseki in one move, with no intention of further expansion along the left side.

[Diagram]
One space jump  

As Black's position is low, subsequently W1 and W3 can expand the top side.

[Diagram]
Diagonal  

The diagonal move at black+circle implies an interest in further expanding the left side with a move at B1. Later, Black can play at a for further expansion.

[Diagram]
Diagonal  

As the black+circle stones form diagonals that are compromised by white+circle, in this variation W1 is a common probing move, which aims at Black's cutting points at a and b. As Black can only defend only one of them, White can then decide a suitable follow-up. Note that the timing of W1 and its follow-up moves is important for achieving the best effect.

[Diagram]
Diagonal  

If Black defends on the 3-3 point, then the W1 and B2 exchange allows White to profit in sente, as black+circle is weakened.

[Diagram]
Diagonal  

If B2 defends the outside cutting point, then W3 to W7 obtains endgame profit at the top side.

[Diagram]
Knight's move  

The knight's move of black+circle also aims at further expansion near B1. Without B1, a move at White a will expose the weakness of the knight's move.

[Diagram]
Knight's move  

When Black ignores white+circle, W1 strikes at the waist and cuts Black off.


Black pincer variant

[Diagram]
A special plan  

Black can play at B1 or a if White's extension frustrates Black plans at the top. (This is bad locally, but may be playable overall.) White's compensation is to fence in Black and create substantial thickness. For both players, knowing how to handle White's thickness is key to playing this variation.

A word about B5: the connection can also be at b. W8 is a little better than c. (Compare with getting ahead with a one-point jump.)

If Black plays atari at B6 instead ...

[Diagram]
A special plan  

... W2 and W4 capture a big corner. W4 at a would be soft. The black+circle stone loses half its purpose.

[Diagram]
Soft  

W4 here is also soft. Black plays a good empty triangle and White has either a cutting point (after White a) or bad shape (after White b).


3-4 point, high approach, inside contact, solid connection last edited by Unkx80 on May 11, 2009 - 13:08
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