33 Point Invasion

  Difficulty: Beginner   Keywords: Joseki, Theory

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. An overview of SL pages about the 3-3 point invasion is given on All About 33 Point Invasion.

Table of contents

Introduction

[Diagram]
The 3-3 point invasion  

Many weak players fear the invasion of W1 in this diagram. Playing Black, they have the idea that their corner territory is taken away, and are, in a sense, correct. After W1, it is White rather than Black who will make territory in this corner.

Nevertheless, Black should welcome this invasion. Black should not see this move as an attack on Black's territory; the 4-4 point is not meant to take the corner, but emphasizes influence and quick development. 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 principle is that White should seek to invade at W1 the move before black would protect the area.


The Standard 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 one usual continuation.

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.

Questions so far?


SqueezeTesujiInJoseki
[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.

Questions so far?


Black wants sente

[Diagram]
Variation to get sente  

Blacks plays the knights jump to get sente. This can be useful if he has a big framework to defend on the upper side. White gets much more on the left side as compensation, with moves like a next. For more discussion see 44Point33InvasionJumpingAway.


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


Further reading


[1]

What if B6 is played as double hane at W7?
The double hane is played if Black wants to keep the corner territory. See 4-4 point 3-3 invasion double hane.
What if B8 is played as hane again at a?
This hane is an overplay, Black leaves many cutting points and will be in trouble soon. For more see RTGProblem31.
Anonymous
What if W7 is instead played at 'c'? Can Black do better than try to capture that stone in a ladder?
Phelan
Two ideas below (a and b). They seem better to me than depending on a ladder, but neither captures the stone directly, if that was what you wanted. c might also work.
[Diagram]
Two ideas  

[2]

Can White change the order of play here?
Better not, see 44Point33InvasionWReversePlayingOrder.
What about the cut at a?
White can not cut at a, see squeeze tesuji in joseki for how to defend.
What can Black do in the corner later?
See hovercraft for Black attacks on the corner and the proper defenses.
Why cover the cut?
See extensive discussion on discussion page, [ext] http://senseis.xmp.net/?topic=2333.

[3]

[Diagram]
black kikashi -- wrong timing?  

I can't find a tesuji for white to continue? B1 can not be caught in a ladder because of the ladder breaker black+circle. Is there a tesuji for white or have white just picked a bad fuseki?

Andy: I wouldn't worry too much about B1 as white. B1 could be considered kikashi, but seems not very effective. White could connect at b of course, or white could extend to either of the a points, and then if black cuts at b, white takes the other a point and now white has two solid groups on the left and top, black is walled into the corner, and the two black stones are too close to white's strength.

That is what my intuition tells me: Ignore the cut. In real games, where you finish the fuseki before jumping to joseki, however, especially the white group at c, doesn't seems that solid after all.

B1 might be close to white's strength, but it can always run away reducing white's potential to next to nothing.

The timings are essential, but I didn't draw out what was going on in the two remaining corners, because I liked to cut it down to the essential question.


33 Point Invasion last edited by 75.133.196.79 on August 22, 2014 - 00:04
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