364463 enclosure 3-3 invasion

    Keywords: Joseki, Life & Death, Tactics
[Diagram]
Yamashita-O  

As black has played 3 moves on the corner he will generally aim to kill a white invasion. An example where B tried to kill occurred in game 4 of the 2003 Kisei match Yamashita Keigo-O Rissei (B) (colours reversed). After the 3-3 invasion W1, B2 here was played, which is a textbook attempt to kill.

Without the black+circle stone white can expect a ko for life in the related 4-4 6-3 enclosure.

[Diagram]
Yamashita-O (continued)  

Yamashita, however, challenged his opponent to kill him, playing W3, W5, and W7. O Rissei then resigned, leaving us with a reading problem, given the exact placing of nearby stones.

Charles Matthews

[Diagram]
 

Here is the position in the game with surrounding stones.



It is the positioning of the black+circle stone that causes some killing lines starting like White a, Black b, White c to fail. It would be nice to have some pro-level analysis of that, though.


[Diagram]
 

JeanPierreTavan? :

Here is Alexandre Dinerchtein's analysis for this position.

The problem begin when white block at W1 instead of W6 in the previous diagram.

[Diagram]
 

After B10, a and b are miai.

Source : [ext] Go4Go.net -- Sample commented games (game #17)


[Diagram]
White should die, but how?  

lavalyn: My best shot at it leaves White with something just less than an L group with leg and gote.

Brian: If B7 at a, doesn't White die?

[Diagram]
An alternative way to kill white, much safer for black.  

jms: I've analyzed this to the bone, and White dies every time this way. If I missed any continuation which allows white to live, ko, or seki, let me know. You can see my analysis here: [ext] http://www.justinstandard.com/sgf/33Invasion.sgf

Minue why not white a, instead of W8. W makes ko.

[Diagram]
White lives small, Black has sente, and huge influence.  

jms: Here is a way for white to live small in the corner. This is perhaps useful in certain situations where the outside is pretty much secured, but a small chance of corner invasion remains.

[Diagram]
White is unconditionally dead.  

lightest? Actually w is dead.

[Diagram]
No way to escape.  
[Diagram]
ko  

Minue Actually White makes ko.

[Diagram]
w dead unconditionally.  

lightest? How about this variation? I think black should damage white's shape as shown.

[Diagram]
corner  

Kangur? I think this is only way to kill white without any ko.

[Diagram]
corner  

Caern I think so, but fuego hadn't kill me in such situation:

[Diagram]
fuego_1  
[Diagram]
fuego_2  

Caern Where fuego make a mistake?

[Diagram]
fuego_3  

364463 enclosure 3-3 invasion last edited by 83.242.199.192 on June 1, 2012 - 16:31
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