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Invading deep enough
  Difficulty: Intermediate   Keywords: MiddleGame

suggested WikiMasterEdit at How to invade

Klaus: Actually, this page should be called Don't invade too deeply? with regard to Andre Engels' and Charles' comments below. Thanks for your help!

[Diagram]
Where should White invade?

In a nine-stone handicap game, I (Klaus) was able to attack a 4473 enclosure with an ikken tobi and faced with the question, how to invade.

[Diagram]
Game sequence (bad for White?)


The game sequence was clearly a failure for White, who failed to create any serious trouble.

Andre Engels: Does not look like a bad sequence for White. And after seeing the complete game diagram (with the black stone being strong) I would go so far as calling it a failure for Black. White started out with a group of weak stones, which are now living with territory. If that's a failure, I would like to see your definition of success.
Charles: I tend to agree with Andre. Now WS is on a point that adds to White's good shape here; and White has sente.
Klaus: Well, I thought it was a success too, but after having seen Takagawa's deep invasion (diagram below) I was not sure anymore. It is nice to hear, that my thoughts during the game where OK.

[Diagram]
Better idea

I still tend to overlook moves like W1 because I feel uncomfortable with "invading" corner territory.

But in this situation, there is no territory to start with!

Sebastian: Interesting! I would have played like you, because I would have been concerned about eye shape for the white group. But I tried some variations, and they all seem to be good for White:

[Diagram]
Possible continuation (1)

[Diagram]
Other continuation (2)


Klaus: I added two more diagrams. The first one seems to be nice for White, but the second one needs further exploration. (Maybe B5 at a, which seems to be bad shape, but it might work.)

[Diagram]
continuation (3)

[Diagram]
Last idea (4)


Floris: Black will usually answer W1 at B2 in the following diagram. Then you can crosscut to try to achieve a nice result or hane underneath to settle without a fight.

Klaus: I guess Black will not answer like that! You named the reason yourself. The second diagram (game sequence) is good enough for Black, who does not have to improve on that.

[Diagram]
Another sequence

Coming in directly with B1 at a has the virtue of forcing White into a cross cut.


As Sebastian stated, the given continuations (1)-(3) seem to be better for White than letting Black settle stones easily as in the "game sequence". The initial B1 seems to be too slack. Of course, Floris is the strongest player mentioned on this page, so there must be something I'm missing about his suggested hane at W2?!


In a German book (Band 16 der Schriftreihe des Deutschen Go-Bundes), Takagawa Kaku presents the following position in a chapter about "How to answer a boshi":

[Diagram]
Takagawa's diagram

He mentions, that B1 should be at a, in order to prevent W4, after which he sees the black stone in the corner in a difficult situation.


Karl Knechtel: I cannot at all see how B1 vs. a has any significant effect on the lower right corner.

Jesse: After B1, W2 is a splitting attack. If Black plays at a, Black can respond to W2 with a play to secure the corner.

[Diagram]
Almost Takagawa's diagram


Klaus: If Black moves out to the other side, W2 does not affect the left-hand corner as much as W2 in Takagawa's diagramm did. The left-hand corner is more stable, and WS is further away from it than WC from the right.


[Diagram]
Not Takagawa's diagram

kokiri: By coincidence, I was looking at a very similar problem in a book (Pro common sense that even amateurs can acquire) which recommended B1. The reasoning was that moving out to the left or right (b or c, say) are approximately miai and so can be left for now; by playing B1, the dangers of B1-W4 above can be avoided.



For reference:

[Diagram]
Lower side in the actual game

Black was quite strong in the top right, but White had a large settled group on the top side.


[Diagram]
So what now?

Andre Engels: One of the proposals was W1 to W5 here. How is one intended to answer after B6?


Klaus: Well, as I said, "Last idea (4)" is to be further investigated, and W5 is probably wrong! But what should White do?

[Diagram]
But what?

[Diagram]
Maybe this?

If White desperately wants to take sente (and White is likely to do so because of the handicap) White might leave the position like that. It is not better than the game continuation though and I would feel more confortable with another stone at a.



Klaus: After the discussion above and the especially disturbing "so what now?" diagram by Andre Engels, I am not sure anymore, how to follow up Takagawa's W4.

[Diagram]
Takagawa's diagram follow up?

Many sequences have to be considered here. Black may start with B1 as in this diagram, but playing at B3 directly or even W2 might both be interesting.



This is a copy of the living page "Invading deep enough" at Sensei's Library.
(OC) 2003 the Authors, published under the OpenContent License V1.0.