Kokiri/3-3 exploration

Sub-page of Kokiri

Block on the wider side, right? - everybody knows that, but after that what comes next...

Basics

[Diagram]

Standard

This is the industry standard. In response to WC, black plays B1 on the "wider side" and play continues with black usually playing the hanging connection at a.

W6 is needed, because otherwise descending to B6 would threaten the corner, meaning that black can turn in sente.

Variation 1

[Diagram]

Variation 1

This is the first variation, played either to take the corner, or to keep sente for black.

Var1: corner

[Diagram]

Variation 1: Corner

here, books and strong players will tell you that giving up a ponnuki is generally too much to lose in order to take the 10 or so points in the corner. It is hard for me to convince myself of this, in particular, i cannot see exactly how white can play from here on. Of course this depends a lot on context.

Questions - 1) when is it right for black to play like this? 2) How should white play after this?

[Diagram]

Example Game K as White, 21/05/05

Strong Player's Comment: the double hane is correct, but the idea should be to keep sente to play, e.g. at a or b, not to take the corner.

[Diagram]

Example Game K as White, 21/05/05

Continuation, Black's two BC stones come under fire, Black makes a slip immediately after and loses the corner. Strong Player's comment: White cannot lose from here. Needless to say Black wins by resig.

see also kokiri/Recentgame10

[Diagram]

When to take the corner

SP's following comment: this is the 'book' example of when to take the corner

B0 good for Black

Presumably the ponnuki is ideal for fighting/attacking, so it is less useful here because black's group is stable in the left.

[Diagram]

When to take the corner

With this (standard?) continuation, White's thickness is staring down at a solid black group - not much use i fear...

Var1:Sente

[Diagram]

Variation 1: Sente

as the regular variation ends in gote for black, this variation is speedier,

questions - when to play this way for BC? what options does WC have?

Note, W2 not W3 W4 connects B5 tenuki


Basic Concepts of 3-3 invasion

The information on this page is meant to be introductory in nature. Stronger kyu and dan players are advised to look at 4-4 point 3-3 invasion joseki instead.

3-3 invasion って何?(introduction)

[Diagram]

The 3-3 point invasion

The classic 3-3 invasion is where one player takes the 3-3 point underneath their opponent's star-point stone, as in W1 in the diagram below.

Beginners encounter this situation a lot due to the number of handicap games they play, but the star-point is much more common also in modern go than the classical style (i.e. pre-shin-fuseki).

The important questions here revolve around timing (i.e. when to play the invasion, or when to play so as to prevent it) & direction (how to respond to the invasion, which variations to choose).

This page looks at the ideas behind the invasion for both black and white, before a summary of the standard sequences that result.


Black's point of view

White's point of view

Standard Sequences

More


Nevertheless, Black should welcome this invasion. Black shouldn't see this move as an attack on Black's territory; the 4-4 point is not meant to take the corner, but to make thickness and seek a balance between territory and influence. The white invasion at W1 is separated from the rest of the board by the black stone on the 4-4 point. By playing correctly Black will get a strong position. Because of this, stronger players play W1 only if the position on the edges is such that a white stone at a or b will come under attack.

White, for his part, should resist the temptation of invading here too soon. The general priciple is that White should seek to invade at W1 the move before black would protect the area.


3-3 Invasion Joseki

[Diagram]

The Standard Joseki

To W1 Black will invariably answer with B2 (or Black at W3, on the other side). To choose which way to block, the general rule here is to block on the wider side, seeking to maximise the usefulness of the outside strength black is building.
W3 ensures that White's corner will not be too small.

B4 is an important move, preventing white from making progress out into the centre.

White plays at W5 to avoid Black playing at the same point.

B6 is the most usual continuation, although the severe double hane of B6 at 7 is played in some circumstances.

Usually crawling along the 2nd line is bad, but W7 is important to prevent Black turning here in sente. White should resist the temptation to continue crawling at a. Every extra point white takes, is far less valuable than the outside strength that Black takes.


What if B8 plays at "a"?

[Diagram]

The joseki continues

Next, White plays hane at W1, and the joseki ends with B4.

White has sente and a few points in the corner, but Black's wall is like a block of concrete, controlling a large part of the board.

This result is regarded as good for Black locally, but is often White's best choice, nonetheless. Later in the game the cut at a might be a problem for Black, see Squeeze for more discussion how and when to defend.

Can White change the order of play here?


3-3 Invasion Prevention

[Diagram]

Prevention

The usual way to prevent the 3-3 point invasion is a stretch at B1 or a depending on where friendly stones are nearby. The one-space jump at b and the diagonal at c can also be used, though they are seen less frequently.

[Diagram]

Preventing the invasion

This shape is also seen in situations like this, where White has played an approach move, with the same intention of preventing the 3-3 invasion


Other Advanced Variations

The diagram above cover the most basic moves, but unsurprisingly, (this is go, after all) there are more complexities and subtleties that one can investigate:

[1] Over-Hane

If black seeks to get more by playing at B1 in the diagram below, then he risks disaster...

[Diagram]

Overplay (1)

B1 here instead of B8 in the joseki (W2 in this diagram) is overdoing things. After W8, Black has problems.

[Diagram]

Overplay (2)

White could also attack the black stones at the left with these moves. Either way, White has destroyed Black's thickness, and has good chances of getting even more.



Charles I've seen a pro as White play directly at B5 after B1 here.


[2]

W plays the reverse order

[Diagram]

Changing the order

Here White swaps the order of play, turning at W1 before playing the hane at W5.

The danger is that Black may be able to answer W3 with B4 rather than the usual B8. This lets Black shut White into the corner with B6 (particularly as 'a' is Black's sente). White ends up with a smaller corner than in the joseki, and Black may be in a position to make territory on the left. The disadavantage for Black is the aji of the cut at 'b'.


There is more detail at 4-4 point 3-3 invasion joseki and the following pages:

Queries

[Diagram]

Queries


mat Very often I ask myself if a 3-3 point invasion still works in the presence of more than one black stone. I've set up a page to discuss which of those work and which don't: 3-3 Point - When Does It Work


Original authors: Andre Engels, Adamzero, JamesA Contributors: Tinia? MarkusKovisto? Reuven Paul Clarke


This is a copy of the living page "Kokiri/3-3 exploration" at Sensei's Library.
(OC) 2005 the Authors, published under the OpenContent License V1.0.
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