TsumegoFromGames61/Solution

Status of marked Black stones  

tderz: I would guess to and due to shortage of liberties, black cannot make a 2nd eye with ->a.

• ->b only leads to ko after ->.
  

• -> is black alive after ->b with miai -> 1 or 5.
  

• If ->, ->b, ->1, ->, ->4, ->, W takes at a and black presses at c.

• If -> 3, ->2, ->5 (no threat to link up), ->b dead shape (no seki escape)