Gokyo Shumyo, Section 1, Problem 4 / Solution

Main line  

After , both pairs of points a/b, and c/d, are miai for life.

Follow-up (i)  

For those who have solved or looked at the earlier problems in this series, this line of play will have become familiar. After , if Black connects at a, White captures three stones to make a second eye on the first line.

Follow-up (ii)  

After then lives. If black a later on then white b is the only move to ensure two eyes.

It would be a mistake for White to answer at a (next diagram).

Mistake in the follow-up move  

Black turns the corner into ko with the throw-in at .

Failure

Wrong (i)  

The 1-2 point is not the right spot to make life for this group. After the sequence to , Black throws in at to leave White with a big eye.

If at , then at , and White has only one eye.

Wrong (ii)  

Descending with is also wrong. Black plays hane at , making miai of a and b for the kill.

Wrong (iii)  

This may be the hardest one to refute. After , White can't play at a because of shortage of liberties. If she captures at b, Black plays at a himself to make the eye false.

Wrong (iv)  

White at here, gives the same result as if White's first mov was played correctly at in this diagram, but White errs with her second move, by answering at (see earlier diagram: Mistake in the follow-up move from the Solution).

White lives in ko, which is not good enough.

• • beginner: in "worng (iv)" white is still alive because after four he can put in 5 like in the diagram below so why does it consider as wrong?
• Hicham:Black can still start a ko. It is better than completely dead, but still far from alive.

Wrong (iv)  

griffin: 6 makes ko