I've been working though Davies' Tesuji book, and I don't think the solution to snapback problem 2 on page 31 works (or at least, it ends in a ko).

Here's the problem (white to play and capture the big clump of balck stones):

Click Here To Show Diagram Code

[go]$$W
$$ -------
$$ ......|
$$ ..OOO.|
$$ .OXOX.|
$$ .OXXXa|
$$ .OX.O.|
$$ .OXO..|
$$ ..OXOX|
$$ ...XX.|
$$ ......|
$$ ..,...|[/go]

The given answer is a.

But I'm worried about black responding with 2:

Click Here To Show Diagram Code

[go]$$W
$$ -------
$$ ......|
$$ ..OOO.|
$$ .OXOX4|
$$ .OXXX1|
$$ .OX.O2|
$$ .OXO.3|
$$ ..OXOX|
$$ ...XX.|
$$ ......|
$$ ..,...|[/go]

And it seems that now we're left with a ko. Have I missed something?

Cheers

(Oh, and this is my first post, so feel free to let me know if I'm using diagrams wrongly or something )

Click Here To Show Diagram Code

[go]$$W
$$ -------
$$ ......|
$$ ..OOO.|
$$ .OXOX4|
$$ .OXXX1|
$$ .OX.O2|
$$ .OXO.3|
$$ ..OXOX|
$$ ...XX5|
$$ ......|
$$ ..,...|[/go]

I think white just plays 5, and black actually can't win the ko. One possibility is double ko that black cannot ever win:

Click Here To Show Diagram Code

[go]$$B
$$ -------
$$ ......|
$$ ..OOO2|
$$ .OXOXX|
$$ .OXXX4|
$$ .OX.O1|
$$ .OXO.O|
$$ ..OXO.|
$$ ...XXO|
$$ .....3|
$$ ..,...|[/go]

Oooh, that's nice.

Cheers, I'd never have seen that.