Tapir: After there is not only one white crane's nest with a liberty, but a hidden second crane's nest for black as well. therefore black has to play a ko and can't capture . Black takes first.
If here, then and works. Subsequently, White at a, b or c leads to a ko.
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there is not only one white crane's nest with a liberty, but a hidden second crane's nest for black as well. therefore black has to play a ko and can't capture 
. Black takes first.
![[Diagram]](diagrams/52/1671eefb6f7bcae6b335d1a302e9715a.png)
here, then 
and 
works. Subsequently, White at a, b or c leads to a ko.