I quote Uberdude's second diagram here:
$$Wcm52
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . O . . . . . . . a X . . . . |
$$ | . X . O . . . . . , . . . . . , X X . |
$$ | . . . . . . . . . . . . . . O X O . . |
$$ | . . X . . . . . . . . . . . . O O . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . X O X . . . . . . . . . . . . . . . |
$$ | . X X O . . . . . . . . . 3 5 . . . . |
$$ | . . O O . . . . . , . . X O 2 , O . . |
$$ | . . . . . . . . . . . 1 O X O 4 . . . |
$$ | . . . . . . . . . . . X O X O X X . . |
$$ | . . . . . . . . . . O O X X X O . . . |
$$ | . . . . . . . . . . O X . . . . O X . |
$$ | . . . . . . . . . . . . . . . O X . . |
$$ | . . . O . . . . . , . . . . . , X . . |
$$ | . . . . . . O . . . . . . X . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ +---------------------------------------+
- Click Here To Show Diagram Code
[go]$$Wcm52
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . O . . . . . . . a X . . . . |
$$ | . X . O . . . . . , . . . . . , X X . |
$$ | . . . . . . . . . . . . . . O X O . . |
$$ | . . X . . . . . . . . . . . . O O . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . X O X . . . . . . . . . . . . . . . |
$$ | . X X O . . . . . . . . . 3 5 . . . . |
$$ | . . O O . . . . . , . . X O 2 , O . . |
$$ | . . . . . . . . . . . 1 O X O 4 . . . |
$$ | . . . . . . . . . . . X O X O X X . . |
$$ | . . . . . . . . . . O O X X X O . . . |
$$ | . . . . . . . . . . O X . . . . O X . |
$$ | . . . . . . . . . . . . . . . O X . . |
$$ | . . . O . . . . . , . . . . . , X . . |
$$ | . . . . . . O . . . . . . X . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ +---------------------------------------+[/go]
I actually think black is not bad here. Eating two stones does not look very large at the first sight. But it has several benefits that can be easily underestimated: (1) the squeeze is gone so black actually gets many more points. (2) white's wall is not perfect with aji at L9. (3) most importantly, the attach at 'a' becomes less effective for white (yes, believe me that is related as I will explain). (4) following (3) if white's 'a' is not very serious, black can first reduce the bottom left corner at C3 or C4 as he has sente.
$$Wc
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . 8 . . . . |
$$ | . . . . . . . . . . . . 7 2 3 4 . . . |
$$ | . . O . . O . . . . . . 9 1 X 6 . . . |
$$ | . X . O . . 0 . . , . . . . 5 , X X . |
$$ | . . . . . . . . . . . . . . O X O . . |
$$ | . . X . . . . . . . . . . . . O O . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . X O X . . . . . . . . . . . . . . . |
$$ | . X X O . . . . . . . . . . . . . . . |
$$ | . . O O . . . . . , . . . . . , O . . |
$$ | . . . . . . . . . . . . . O O . . . . |
$$ | . . . . . . . . . . . O O X O X X X . |
$$ | . . . . . . . . . . . O X X X O . O O |
$$ | . . . . . . . . . . X X O . . O O X X |
$$ | . . . . . . . . . . . . X X X O X O . |
$$ | . . . O . . . . . , . . . . O X X . . |
$$ | . . . . . . O . . . . . . X . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ +---------------------------------------+
- Click Here To Show Diagram Code
[go]$$Wc
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . 8 . . . . |
$$ | . . . . . . . . . . . . 7 2 3 4 . . . |
$$ | . . O . . O . . . . . . 9 1 X 6 . . . |
$$ | . X . O . . 0 . . , . . . . 5 , X X . |
$$ | . . . . . . . . . . . . . . O X O . . |
$$ | . . X . . . . . . . . . . . . O O . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . X O X . . . . . . . . . . . . . . . |
$$ | . X X O . . . . . . . . . . . . . . . |
$$ | . . O O . . . . . , . . . . . , O . . |
$$ | . . . . . . . . . . . . . O O . . . . |
$$ | . . . . . . . . . . . O O X O X X X . |
$$ | . . . . . . . . . . . O X X X O . O O |
$$ | . . . . . . . . . . X X O . . O O X X |
$$ | . . . . . . . . . . . . X X X O X O . |
$$ | . . . O . . . . . , . . . . O X X . . |
$$ | . . . . . . O . . . . . . X . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ +---------------------------------------+[/go]
This is the real game: white got a very solid shape after

, black had to reduce at

which as the game turned out was not an easy fight. How many of you have wondered why

could not capture that stone instead to prevent white from sealing the top side? Here is why:
$$Bcm6 :b8: = :ws:
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . 1 . . . . |
$$ | . . . . . . . . . . . . . X @ X 6 8 9 |
$$ | . . O . . O . . . . . . . O X 2 4 5 . |
$$ | . X . O . . . . . , . . . . O 7 X X . |
$$ | . . . . . . . . . . . . . . O X O 0 . |
$$ | . . X . . . . . . . . . . . . O O . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . X O X . . . . . . . . . . . . . . . |
$$ | . X X O . . . . . . . . . . . . . . . |
$$ | . . O O . . . . . , . . . . . , O . . |
$$ | . . . . . . . . . . . . . O O . . . . |
$$ | . . . . . . . . . . . O O X O X X X . |
$$ | . . . . . . . . . . . O X X X O . O O |
$$ | . . . . . . . . . . X X O . . O O X X |
$$ | . . . . . . . . . . . . X X X O X O . |
$$ | . . . O . . . . . , . . . . O X X . . |
$$ | . . . . . . O . . . . . . X . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ +---------------------------------------+
- Click Here To Show Diagram Code
[go]$$Bcm6 :b8: = :ws:
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . 1 . . . . |
$$ | . . . . . . . . . . . . . X @ X 6 8 9 |
$$ | . . O . . O . . . . . . . O X 2 4 5 . |
$$ | . X . O . . . . . , . . . . O 7 X X . |
$$ | . . . . . . . . . . . . . . O X O 0 . |
$$ | . . X . . . . . . . . . . . . O O . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . X O X . . . . . . . . . . . . . . . |
$$ | . X X O . . . . . . . . . . . . . . . |
$$ | . . O O . . . . . , . . . . . , O . . |
$$ | . . . . . . . . . . . . . O O . . . . |
$$ | . . . . . . . . . . . O O X O X X X . |
$$ | . . . . . . . . . . . O X X X O . O O |
$$ | . . . . . . . . . . X X O . . O O X X |
$$ | . . . . . . . . . . . . X X X O X O . |
$$ | . . . O . . . . . , . . . . O X X . . |
$$ | . . . . . . O . . . . . . X . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ +---------------------------------------+[/go]
If

captures, first of all black cannot fight a ko there because white has many ko threats near the squeeze (assuming AlphaGo knows how to fight ko properly

). So black has to connect at

. Locally black can defend the corner without problem. However, white can get

in sente. As a result, this would happen ......
$$Wc
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . X . X . . |
$$ | . . . . . . . . . . . . . X X X O O X |
$$ | . . O . . O . . . . . . . O X O O X . |
$$ | . X . O . . . . . , . . . . O X X X . |
$$ | . . . . . . . . . . . . . . O X O O . |
$$ | . . X . . . . . . . . . . . . O O . . |
$$ | . . . X . . . . . . . . . . . . . X 1 |
$$ | . X O X . . . . . . . . . . . . . X O |
$$ | . X X O . . . . . . . . . . . . . X O |
$$ | . . O O . . . . . , . . . . . , O X O |
$$ | . . . . . . . . . . . . . O O . . X O |
$$ | . . . . . . . . . . . O O X O X X X O |
$$ | . . . . . . . . . . . O X X X O . O O |
$$ | . . . . . . . . . . X X O . . O O X . |
$$ | . . . . . . . . . . . . X X X O X O O |
$$ | . . . O . . . . . , . . . . O X X . . |
$$ | . . . . . . O . . . . . . X . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ +---------------------------------------+
- Click Here To Show Diagram Code
[go]$$Wc
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . X . X . . |
$$ | . . . . . . . . . . . . . X X X O O X |
$$ | . . O . . O . . . . . . . O X O O X . |
$$ | . X . O . . . . . , . . . . O X X X . |
$$ | . . . . . . . . . . . . . . O X O O . |
$$ | . . X . . . . . . . . . . . . O O . . |
$$ | . . . X . . . . . . . . . . . . . X 1 |
$$ | . X O X . . . . . . . . . . . . . X O |
$$ | . X X O . . . . . . . . . . . . . X O |
$$ | . . O O . . . . . , . . . . . , O X O |
$$ | . . . . . . . . . . . . . O O . . X O |
$$ | . . . . . . . . . . . O O X O X X X O |
$$ | . . . . . . . . . . . O X X X O . O O |
$$ | . . . . . . . . . . X X O . . O O X . |
$$ | . . . . . . . . . . . . X X X O X O O |
$$ | . . . O . . . . . , . . . . O X X . . |
$$ | . . . . . . O . . . . . . X . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ +---------------------------------------+[/go]
I will leave you guys to decode the sequence, but basically with the

sente in the previous diagram, white can connect from the first line!
To summarise, in Uberdude's diagram, it may look like that capturing two stones are not quite big, but in fact it is much bigger because white's top side indirectly affected and reduced in value.
So back to the Chunlan Cup game, we can see Mi Yuting's S10/R11 exchange actually makes sense!