I'm struggling a bit to work out a move order in which O would play the triangled atari and not expect black to munch the corner (ko in tripod group with extra leg notwithstanding). Maybe like this:
- Click Here To Show Diagram Code
[go]$$B
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . 5 . . . . . . . . . . . . . |
$$ | . . 1 , . . . . . , . . . . . 4 . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . 8 . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . 6 . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . 3 . . . . . , . . . . . 2 0 . . |
$$ | . . . . . 7 . . . . . . . . . . 9 . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ +---------------------------------------+[/go]
Big extend to 8 is in fashion in post-AG world.
- Click Here To Show Diagram Code
[go]$$Bm11
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . X . . . . . . . . . . . . . |
$$ | . . X , . . . . . , . . . . . O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . 8 . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . , . . . . 2 O O . . |
$$ | . . 0 . . X . . . . . . 5 4 . 1 X 6 . |
$$ | . . . . . . . . . . . 7 . 3 . . . 9 . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ +---------------------------------------+[/go]
White has ladder which probably explains black's choice of 17 not 19 (but given that why not 15 as extend not hane? LZ agrees its better). 20 invasion is follow-up of ignored 18.
- Click Here To Show Diagram Code
[go]$$Bm21
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . X . . . . . . . . . . . . . |
$$ | . . X , . . . . . , . . . . . O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . 4 . . . . . . . . . . . . . |
$$ | . . O . O 3 . . . . . . . . . . . . . |
$$ | . 5 7 . . 8 . . . . . . . . . . . . . |
$$ | . 2 1 X d e . . . , . . . . O O O . . |
$$ | . 6 O 9 c X . . . . . . X O . X X O . |
$$ | . . . . a b . . . . . X . X . . . X . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ +---------------------------------------+[/go]
23 attach is a fairly standard tesuji in the shape which helps deal with the cut at
e should the standard corner sequence a-d happen. Not sure when black would have played it but this order seems plausible, Then O's atari of 28 instead of slide to
a is presumably fighting spirit and trying to make black's attachment into a bad exchange, but focusing too much on that and not how his 3-3 invasion stones also became bad exchanges. Reminds me rather of Lee Sedol vs AG game 3 at lower left corner.