PillboxThePlayer/EyeSpacesQuestions

Sub-page of PillboxThePlayer

Table of contents Table of diagrams
White definitely alive?
maybe...
Yes, B1 seems to lead to forced seki for B.
White can block...
White definitely alive?
Omitting W4, one outside liberty


Shape from a game on 2008-03-12

This is a shape that came up during a game I was playing (poorly) and won.

My opponent resigned, and then asked to play out the game anyway. The Score Randomizer during the review indicated B+3.5, and I didn't pay much attention to it. I figured I had lost and was lucky that my opponent only resigned because of a failed invasion.

Later, after reviewing the game, I checked the Score Randomizer again and it considered this corner dead. Which was contrary to my initial reading.

[Diagram]
White definitely alive?  
[Diagram]
maybe...  

pillbox: thoughts?

[Diagram]
Yes, B1 seems to lead to forced seki for B.  

This leads to the position in Seki in the corner example 2. Any different response looks worse for W. Note that W next at 1-1 starts an infinite cycle of "W 1-1, B take, W take, B pass". -- ChrisBall.

Karl Knechtel: See also sending two returning one.

[Diagram]
White can block...  

pillbox: Looks like W can block at a, b, or c to force life.


[Diagram]
White definitely alive?  

LukeNine45: With two outside liberties, white can play a and is alive. With only one, W4 is a ko threat to live outright, but black can fill an outside liberty to keep it seki. With no outside liberties, white omits W4 and it is a gote seki for black. (Later: The rest of this paragraph is completely wrong:) Note that this W2 is better than the one in the above diagrams, because here white can omit W4. Above, if white does so, black can make a ko.


Karl Knechtel: Er, Black can still make a ko if White omits W4 in the "improved" line (unless there are two outside liberties, in which case White can play oshitsubushi)...

[Diagram]
Omitting W4, one outside liberty  

A Black capture at b would either leave a dead bulky five inside, or allow Black to capture by me ari me nashi, and White at b is dead in gote, so White must play a, and Black takes first in the resulting ko.

LukeNine45: Yes, I don't know what I was thinking.


PillboxThePlayer/EyeSpacesQuestions last edited by LukeNine45 on March 14, 2008 - 19:50
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