Kyu Exercise 211 / Solution

Solution  

The descent at makes miai of making the second eye at a and connecting at b. Hence White lives unconditionally.

Failure  

Unlike the position described in two stones on the third line can make an eye, the hane at is wrong. Although White can live by ko with and , it is inferior to the unconditional life in the solution.

Failure  

Again this is a ko, but ko is considered a failure in this problem.

Failure  

can also descend, aiming to connect with , but can start a throw-in ko. Among all the kos presented, this is probably the best for White because White takes the ko first.

Note: This sequence is the second solution in the original problem, because it is not possible for Black to throw-in at without the stone.

Failure  

The more usual looking tiger's mouth described in two stones on the third line can make an eye does not work in this case, because the existence of the stones meant that if cuts after , then can capture the stone in a ladder.

Failure  

Connecting with doesn't make an eye either.

Failure  

Make a hane at the other direction with allows and to kill the group unconditionally.