Gokyo Shumyo, Section 1, Problem 8 / Solution

Enlarge eye-space  

Enlarging the eye space with is the key move, and probably not too hard to come up with. After Black blocks with , White's descent with is tesuji. Whatever Black tries hereafter, he can't reduce White to one eye anymore.

Wrong follow-up (i)  

If White forgets about the descent tesuji, and connects with , destroys the eye space and the hane at reduces to one eye. The order of and can be inverted. at also kills.

Wrong follow-up (ii)  

White's follow-up at here is also a mistake. makes miai of a and b to kill White. at c is answered by Black d, creating shortage of liberties. (Note: should not be at b: White blocks at c and has a ko to live.)

Awkward continuation?  

Mike Terry: Depending on what is further up the board, White may be able to continue from the previous diagram, resisting stubornly as shown here. After , White will either live in the corner or break out up the left hand side. Black can prevent all this by playing at a, leading to a ko, but in any case this option is clearly inferior for White, compared to living unconditionally as in the proper solution.

Wrong(i)  

If White plays the 1-2 point first, answered by Black taking the other, and then plays the -- exchange as in the correct answer, creates shortage of liberties.

at a means dying in gote.
at b provokes atari at c, White connects at a and dies.
Only at d deserves further attention.

A throw-in tesuji  

The throw in at kills. If at , then at makes life in seki. at also works.

Wrong (ii)  

If White plays this 1-2 point, Black has an easy time killing White.

Enlarge eye-space  

demetria: I've only just started studying Go, so I'm having a hard time imagining this. What happens if black plays at A? Doesn't that stop white from enlarging the eye space?

Enlarge eye-space  

unkx80: captures the stone. Please see chapel.