Endgame Tesuji 16
When the life of the White group depends on an eye in the corner the correct is especially crucial.
symplicity: Well, white can still live this way in double ko. It's not as good to live this way because of the ko threats for other kos, but it's not as bad as just ko...
tapir: Ok, so I changed the diagram that it is really a ko, can we agree on that? Double ko is a blind spot to me as you noticed.