Gokyo Shumyo, Section 1, Problem 3 / Solution

Main line  

After , which makes an eye at the circled point, a and b are miai for life. at c also lives.

2 and 3 are miai (i)  

After , Black has real eyes at the circled points.

2 and 3 are miai (ii)  

It seems as if creates a false eye, but the capture of three stones on the first line with results in a real eye.

2 and 3 are miai (ii continued)  

Even if White throws in at , Black lives with .

Variation  

If White captures a Black stone with , or a makes a second eye. However, if Black doesn't respond, White a kills the group.

Wrong (i)  

at the other 1-2 point is wrong. With , Black is dead. Even if Black is allowed two moves in a row, he can't live.

Wrong (ii)  

When Black plays here, White kills with . ( at is an inferior way to kill, because after Black and White a, Black gets some concrete threats at c.)

Wrong (iii)  

Connecting with Black , as shown here, is also wrong. and leave a and b as miai for the kill.

Another way to live  

Making the eye as large as possible, with here, also lives.

Difference ( at )  

To this way of living, White can seal the right side in sente. is necessary to avoid ko.