One Thousand and One Life-and-Death Problems / Problem 75 discussion

Solution Diagram  

This lives.

Ko threats  

White gets , , and at one of the points; a total of three ko threats.

Is this also a solution?  

A question was raised: Is also a solution? The answer is given below.

Failure 1  

This fails. White plays and the shape is dead. If at any time Black captures the four White stones with , then kills (Black cannot make two eyes due to damezumari).

Failure 2  

looks fancy, but it fails because of the same reason ( at ).