Under the Stones is for itself (in my opinion) an often missed Tesuji but to find it and think the group is dead only to realize there's a Ko in the position really makes this problem a nice but nasty little one : D
By the way, the problem is from "The Art of Capturing Stones" and there it is labelled that Black is dead.
$$Bc Status? $$ ------------------ $$ . . O X . . O X X . . | $$ . O X X O . O O X O . | $$ . O O O X X X X X O . | $$ . . . O O . . . O . . | $$ . . . . . O O O . . . | $$ . . . . . . . . . . . | $$ . . . . . . . . . . . | $$ . . . . . . . . . . . |
[go]$$Bc Status? $$ ------------------ $$ . . O X . . O X X . . | $$ . O X X O . O O X O . | $$ . O O O X X X X X O . | $$ . . . O O . . . O . . | $$ . . . . . O O O . . . | $$ . . . . . . . . . . . | $$ . . . . . . . . . . . | $$ . . . . . . . . . . . |[/go]
$$Bc Status? $$ ------------------ $$ . . O X . . O X X . . | $$ . O X X O . O O X O . | $$ . O O O X X X X X O . | $$ . . . O O . . . O . . | $$ . . . . . O O O . . . | $$ . . . . . . . . . . . | $$ . . . . . . . . . . . | $$ . . . . . . . . . . . |
[go]$$Bc Status? $$ ------------------ $$ . . O X . . O X X . . | $$ . O X X O . O O X O . | $$ . O O O X X X X X O . | $$ . . . O O . . . O . . | $$ . . . . . O O O . . . | $$ . . . . . . . . . . . | $$ . . . . . . . . . . . | $$ . . . . . . . . . . . |[/go]
$$Bc Status? $$ ------------------ $$ . 1 O X . . O X X . . | $$ . O X X O . O O X O . | $$ . O O O X X X X X O . | $$ . . . O O . . . O . . | $$ . . . . . O O O . . . | $$ . . . . . . . . . . . | $$ . . . . . . . . . . . | $$ . . . . . . . . . . . |
[go]$$Bc Status? $$ ------------------ $$ . 1 O X . . O X X . . | $$ . O X X O . O O X O . | $$ . O O O X X X X X O . | $$ . . . O O . . . O . . | $$ . . . . . O O O . . . | $$ . . . . . . . . . . . | $$ . . . . . . . . . . . | $$ . . . . . . . . . . . |[/go]
$$Bc Status? $$ ------------------ $$ . 1 . X 2 . O X X . . | $$ . O X X O 3 O O X O . | $$ . O O O X X X X X O . | $$ . . . O O . . . O . . | $$ . . . . . O O O . . . | $$ . . . . . . . . . . . | $$ . . . . . . . . . . . | $$ . . . . . . . . . . . |
[go]$$Bc Status? $$ ------------------ $$ . 1 . X 2 . O X X . . | $$ . O X X O 3 O O X O . | $$ . O O O X X X X X O . | $$ . . . O O . . . O . . | $$ . . . . . O O O . . . | $$ . . . . . . . . . . . | $$ . . . . . . . . . . . | $$ . . . . . . . . . . . |[/go]
$$Bc Status? $$ ------------------ $$ . 1 4 . 2 . O X X . . | $$ . O . . O 3 O O X O . | $$ . O O O X X X X X O . | $$ . . . O O . . . O . . | $$ . . . . . O O O . . . | $$ . . . . . . . . . . . | $$ . . . . . . . . . . . | $$ . . . . . . . . . . . |
[go]$$Bc Status? $$ ------------------ $$ . 1 4 . 2 . O X X . . | $$ . O . . O 3 O O X O . | $$ . O O O X X X X X O . | $$ . . . O O . . . O . . | $$ . . . . . O O O . . . | $$ . . . . . . . . . . . | $$ . . . . . . . . . . . | $$ . . . . . . . . . . . |[/go]
$$Bc Status? $$ ------------------ $$ . 1 4 . 2 5 . X X . . | $$ . O . b O 3 a . X O . | $$ . O O O X X X X X O . | $$ . . . O O . . . O . . | $$ . . . . . O O O . . . | $$ . . . . . . . . . . . | $$ . . . . . . . . . . . | $$ . . . . . . . . . . . |
[go]$$Bc Status? $$ ------------------ $$ . 1 4 . 2 5 . X X . . | $$ . O . b O 3 a . X O . | $$ . O O O X X X X X O . | $$ . . . O O . . . O . . | $$ . . . . . O O O . . . | $$ . . . . . . . . . . . | $$ . . . . . . . . . . . | $$ . . . . . . . . . . . |[/go]
$$Bc $$ ----------------------+ $$ . . O X 1 . O X X . . | $$ . O X X O . O O X O . | $$ . O O O X X X X X O . | $$ . , . O O . . , O . . | $$ . . . . . O O O . . . | $$ . . . . . . . . . . . |
[go]$$Bc $$ ----------------------+ $$ . . O X 1 . O X X . . | $$ . O X X O . O O X O . | $$ . O O O X X X X X O . | $$ . , . O O . . , O . . | $$ . . . . . O O O . . . | $$ . . . . . . . . . . . |[/go]
$$Bc $$ ----------------------+ $$ . . O X 1 . O X X . . | $$ . O X X O . O O X O . | $$ . O O O X X X X X O . | $$ . , . O O . . , O . . | $$ . . . . . O O O . . . | $$ . . . . . . . . . . . |
[go]$$Bc $$ ----------------------+ $$ . . O X 1 . O X X . . | $$ . O X X O . O O X O . | $$ . O O O X X X X X O . | $$ . , . O O . . , O . . | $$ . . . . . O O O . . . | $$ . . . . . . . . . . . |[/go]
next atari and under the stones
There is no under the stones in your attempt here.
$$Bc $$ ----------------------+ $$ . 1 a X 2 b O X X . . | $$ . O X B O 3 W O X O . | $$ . O O O X X X X X O . | $$ . , . O O . . , O . . | $$ . . . . . O O O . . . | $$ . . . . . . . . . . . |
[go]$$Bc $$ ----------------------+ $$ . 1 a X 2 b O X X . . | $$ . O X B O 3 W O X O . | $$ . O O O X X X X X O . | $$ . , . O O . . , O . . | $$ . . . . . O O O . . . | $$ . . . . . . . . . . . |[/go]
after 1,2,a,b the two circles are miai: both circles are under the stones, no? But I admit I had it wrong again