Here is the published solution for Hitachi Number 9.
After Black 1, a and b are miai.
In this variation, White cannot play at c because of a shortage of liberties.
Once Black connects the square-marked group to the circle-marked stone White can not keep these stones from escaping into the middle of the board where they can (presumably) link to a strong black group or make two eyes.
Thanks for the comment. I'll amend the original problem to include this assumption.
The following variation aroused a bit of debate in rec.games.go. Apparently the published solution did not show how to continue after Black 3...
How should Black continue? He must not let White play a and b or else Black will die. Black can keep White from connecting by playing at a, b, or c. At c is my current preference:
White's marked group only has six liberties while Black's marked group has at least seven.
Can anyone improve on this?
This sequence is confusing: Move number 9 prevents White from playing at a in sente, but lets White live with 10. Black could kill White by playing at 10 himself.
White 2 makes one eye and now threatens the connection at a or the second eye at b. However, she has a weakness at c, as shown.