topazg, I'll be travelling during the next two weeks, and it's unlikely I'll have time to make moves during that time. Hence, should you fancy taking 14 days to think over your next move, let nothing stop you from doing so.
$$Wcm70 Prisoners:
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . X . . . . . . . . . . |
$$ | . . . . . X X . X O X O . . . O X . . |
$$ | . . . X . O X . O X X . . . O X X . . |
$$ | . . . X O . . . O . . . . O X X X . . |
$$ | . . . X . . . . . O . . . . O X . . . |
$$ | . . O . . O . . . . . . . . O O X . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . X X . . |
$$ | . . . . . . . . . . . . . . . . O 1 . |
$$ | . . . . . . O . . X . . . O . O . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . O O O O . . . . . . . . . . . . . . |
$$ | O X X X O X . . . , . . . O . O X X . |
$$ | . O X O X . . . . . . . . . . O O X . |
$$ | . . X . X . . . . . . . . . . . . O . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . X . . . . . . . . . . |
$$ | . . . . . X X . X O X O . . . O X . . |
$$ | . . . X . O X . O X X . . . O X X . . |
$$ | . . . X O . . . O . . . . O X X X . . |
$$ | . . . X . . . . . O . . . . O X . . . |
$$ | . . O . . O . . . . . . . . O O X . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . X X . . |
$$ | . . . . . . . . . . . . . . . . O 1 . |
$$ | . . . . . . O . . X . . . O . O . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . O O O O . . . . . . . . . . . . . . |
$$ | O X X X O X . . . , . . . O . O X X . |
$$ | . O X O X . . . . . . . . . . O O X . |
$$ | . . X . X . . . . . . . . . . . . O . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------
- Click Here To Show Diagram Code
[go]$$Wcm70 Prisoners:
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . X . . . . . . . . . . |
$$ | . . . . . X X . X O X O . . . O X . . |
$$ | . . . X . O X . O X X . . . O X X . . |
$$ | . . . X O . . . O . . . . O X X X . . |
$$ | . . . X . . . . . O . . . . O X . . . |
$$ | . . O . . O . . . . . . . . O O X . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . X X . . |
$$ | . . . . . . . . . . . . . . . . O 1 . |
$$ | . . . . . . O . . X . . . O . O . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . O O O O . . . . . . . . . . . . . . |
$$ | O X X X O X . . . , . . . O . O X X . |
$$ | . O X O X . . . . . . . . . . O O X . |
$$ | . . X . X . . . . . . . . . . . . O . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
I briefly looked at a few alternatives, but the simple descent seems easily best. Killing the group outright (with something akin to "a") seems impossible. I also looked at moves like "b" with the intent to give easy life to the group below in exchange for additional strength against the two Black stones above. However, the simple descent should be sufficient against the two stones above, while there is more benefit still to be had from attacking the Black group below.
I expect a sequence akin to this one:
$$Bc
$$ . . . . . . . . . |
$$ . . . . . X X . . |
$$ . . . . . . O . . |
$$ . . . O . O . a . |
$$ . . . . . . X b . |
$$ . . . . . X . . . |
$$ . . . . . . . . . |
$$ . . . O . O X X . |
$$ . . . . . O O X . |
$$ . . . . . . . O . |
$$ . . . . . . . . . |
$$ ------------------
$$ . . . . . . . . . |
$$ . . . . . X X . . |
$$ . . . . . . O . . |
$$ . . . O . O . a . |
$$ . . . . . . X b . |
$$ . . . . . X . . . |
$$ . . . . . . . . . |
$$ . . . O . O X X . |
$$ . . . . . O O X . |
$$ . . . . . . . O . |
$$ . . . . . . . . . |
$$ ------------------
- Click Here To Show Diagram Code
[go]$$Bc
$$ . . . . . . . . . |
$$ . . . . . X X . . |
$$ . . . . . . O . . |
$$ . . . O . O . a . |
$$ . . . . . . X b . |
$$ . . . . . X . . . |
$$ . . . . . . . . . |
$$ . . . O . O X X . |
$$ . . . . . O O X . |
$$ . . . . . . . O . |
$$ . . . . . . . . . |
$$ ------------------[/go]
I expect a sequence akin to this one:
$$Bc
$$ -------------------
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ X O . . . O X . . |
$$ X . . . O X X . . |
$$ . . . O X X X . . |
$$ . . . . O X . . . |
$$ . . . . O O X . . |
$$ . . . . . . 6 . . |
$$ . . . . . . . . . |
$$ . . . . . X X . . |
$$ . . . . . . O O . |
$$ . . . O . O . 5 . |
$$ . . . . . 4 X . . |
$$ . . . . . X . 1 . |
$$ . . . . . 2 3 . . |
$$ . . . O . O X X . |
$$ . . . . . O O X . |
$$ . . . . . . . O . |
$$ . . . . . . . . . |
$$ ------------------
$$ -------------------
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ X O . . . O X . . |
$$ X . . . O X X . . |
$$ . . . O X X X . . |
$$ . . . . O X . . . |
$$ . . . . O O X . . |
$$ . . . . . . 6 . . |
$$ . . . . . . . . . |
$$ . . . . . X X . . |
$$ . . . . . . O O . |
$$ . . . O . O . 5 . |
$$ . . . . . 4 X . . |
$$ . . . . . X . 1 . |
$$ . . . . . 2 3 . . |
$$ . . . O . O X X . |
$$ . . . . . O O X . |
$$ . . . . . . . O . |
$$ . . . . . . . . . |
$$ ------------------
- Click Here To Show Diagram Code
[go]$$Bc
$$ -------------------
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ X O . . . O X . . |
$$ X . . . O X X . . |
$$ . . . O X X X . . |
$$ . . . . O X . . . |
$$ . . . . O O X . . |
$$ . . . . . . 6 . . |
$$ . . . . . . . . . |
$$ . . . . . X X . . |
$$ . . . . . . O O . |
$$ . . . O . O . 5 . |
$$ . . . . . 4 X . . |
$$ . . . . . X . 1 . |
$$ . . . . . 2 3 . . |
$$ . . . O . O X X . |
$$ . . . . . O O X . |
$$ . . . . . . . O . |
$$ . . . . . . . . . |
$$ ------------------[/go]
first happily because White will just extend at the bottom, which is big, and much though I don't like to get sealed in, White hasn't got any points at my central stone is at least somewhat supported by 
before jumping, but I should think about it some more. Also, I need to make sure that I don't need to exchange "a" for "b"--an exchange I'd rather avoid.