Solution  

Black can't save .

(Later) Actually a ko with at r

 

is a double threat ladder-maker but is a double ladder breaker.

 

For other , White just starts taking away Black's liberties.

 

unkx80: I never seen this before. But I think after , Black can get at least a ko. Can Black do better?

char: I can't find anything better than a ko.

 

unkx80: Actually, this is the main line. I think the whole main line solution is about 30 moves long; how many amateurs can read this long without using a go board as an aid?

char: Let's open the can of variations =)

 

Ladder 1

( at )  

Ladder 2

 

Double Ladder Breaker

Since the two ladders are parallel, theoretically any white stone between them breaks both ladder.

However, playing a white stone at d or further doesn't work (the diagram on the right).

Double Ladder Breaker 'a'

 

Double threat, again.

is not the only move; there are several other working moves.

 

Double Ladder Breaker 'b'

 

After , there are two ladders, starting with x and y.

 

White can once again try to break both ladder by playing at or r, but it won't work.

( at )  

Double Ladder Breaker 'c'

 

???