Go Wizardry

Correct Solution 1 (Squeezing from the Outside)

It is no good to continue focusing on the two Black stones that are in atari. With the hane of White 1, then 3, the shape in the corner is only good for making one eye. The capture of Black "a" does not change the condition of White always being able to play at "b."

Correct Solution 2 (Equivalent Options [Miai])

Black 4 and White 5 are equivalent options [miai]. If Black 5, White 4 still kills the group.

Diagram 1 (Ko)

The attachment of White 1 does not strike at the vital point.

Diagram 2 (Alive)

Capturing the two stones is the same as giving up a move.