Tsumego From Games 55 / Solution

Sub-page of TsumegoFromGames55
[Diagram]
corner  

This also lives.

Dieter: Yes, but with less points. The question concerned the status of the White group if White plays elsewhere.

ilan: The Oracle of ilan answered your original question and will now move on.

Dieter: Maybe someone else wants to try if the group could live without White answering locally.


[Diagram]
My attempt  

Grauniad: I don't see how White can live after a Black move at the same point.

[Diagram]
Answer  

B9 prevents ko and makes miai of a and b. This and move B5 are not obvious to me, and I suspect there may be holes in the reasoning.

[Diagram]
Different Answer  

Ed?: White is alive here at 'a' or 'b'.

[Diagram]
Different Answer  

[Diagram]
ko  

ed?: B3 here threatens to separate the the white stones by pushing through at W4. If the exchange of W8 for B9 is not sente then black can kill.

[Diagram]
ko  

White throws in with W3 to make a ko. White will play at either point 'a' to finish the ko.

[Diagram]
Alternative for black 7  

White is alive here.

[Diagram]
Alternative for black 5  

White is alive after W2


[Diagram]
Increasing eye space  

If the exchange of W8 for B9 is not sente for white black can kill.

[Diagram]
approach ko  

Black can get a sente seki by exchanging 'a' for 'b'. Playing 'c' instead leaves open the possibility of a ko. White 'b' in response to 'c' leaves a 1000 yr ko, although if white starts it early by throwing in at 'a' it is a direct ko for white but black will need a lot of approach moves. If black can play 'c' and white tenuki's, black 'b' makes it a direct ko.

This diagram seems to be white's best option.


[Diagram]
Playing underneath 1  

Here white dies. W3 at B4 would give ko after black pushes through at W3.

[Diagram]
Playing underneath 2  

'a' and 'b' are miai so white must fight the ko


[Diagram]
Not clever  

Resisting with W2 is clearly bad, white collapses.


[Diagram]
Seki  

This attack leads to seki. W6 at 'a' would lead to ko. Again white is dead if the exchange of W8 for B9 isn't sente.

[Diagram]
Seki  

If B2 at W3 then white lives with territory at 2.

(Hicham): Isn't 4 atari?

Ed? True white needs to exchange 'a' for 'b' before playing B5


[Diagram]
corner  

[alternative: alive --Dieter


Tsumego From Games 55 / Solution last edited by Unkx80 on July 8, 2008 - 10:52
RecentChanges · StartingPoints · About
Edit page ·Search · Related · Page info · Latest diff
[Welcome to Sensei's Library!]
RecentChanges
StartingPoints
About
RandomPage
Search position
Page history
Latest page diff
Partner sites:
Go Teaching Ladder
Goproblems.com
Login / Prefs
Tools
Sensei's Library