HermanHiddema/OGS Triple Ko analysis

Sub-page of HermanHiddema

Assuming the game finished like this, and now both players pass.

What is the status of black and white in the lower right, given Japanese rules?

Reference diagram  

Under Japanese rules, during the determination of life and death, neither player may ever retake any ko unless he has passed for that specific ko ([ext] Japanese rules section 7.2)

If black tries to prove that white is dead, play goes as follows:

Black tries  

After B3, white cannot retake at white+circle, due to the aforementioned extra rule. Given that the whole white group is in atari, white therefore cannot avoid capture.

If white tries to prove that black is dead, play goes as follows:

white tries  

W3: White passes to be allowed to recapture at white+circle

B4: Black passes to be allowed to recapture at black+circle

This can go on indefinitely, therefore white cannot capture black.

HermanHiddema/OGS Triple Ko analysis last edited by HermanHiddema on July 26, 2014 - 20:51
RecentChanges · StartingPoints · About
Edit page ·Search · Related · Page info · Latest diff
[Welcome to Sensei's Library!]
Search position
Page history
Latest page diff
Partner sites:
Go Teaching Ladder
Login / Prefs
Sensei's Library