Beginner Exercise 110 / Solution

Solution: ko  

Black can connect by winning this ko.

A different ko: white's mistake  

If white plays here, it's also a ko, but then black has a and b as local ko threats. So the first diagram is better for white.

Failure  

If Black plays the symmetric point, White cuts off with this cut through the keima.

Variation  

This is another variation. Black tries a kind of "monkey jump on the second line", then White plays the attachment at . Next, descending at is key.