Gokyo Shumyo, Section 1, Problem 10 / Solution

Black lives  

If we have gone through the previous problems of this series, we will have developed a feeling for this kind of problem and instinctively look for two possibilities: the 1-2 point and the 2-2 point. Here, Black 1 at the 1-2 point is correct. The exchanged marked stones are an indicator.

Continuation  

If White can do anything, she has to prevent the eye at the circled point so she plays 2. After 3, she can only connect at 4.

Continuation  

As we know by now, capturing three stones suffices for an eye.

Wrong (i)  

Black 1 at the 2-2 point is wrong. White 2 gives birth to a bent four in the corner shape and Black dies.

Wrong (i) variation  

is tricky, and is the correct answer. If at a, then Black plays at and lives.

Wrong (ii)  

For the sake of repetition, taking a stone with Black 1 is wrong too, for White creates a bulky five shape with 2 and strikes at the vital point with 4. If you have been solving tsumego for a while, 2 and 4 are moves you even don't have to think about anymore.

Wrong (iii)  

How about enlarging the eyespace with 1 here ? Well, that's perhaps not too easy to refute and demands some explanation, so I'll make it Gokyo Shumyo, Section 1, Problem 10b.