First of all let me clarify this: when I said "comfortable win" I meant to say that the difference on board is rather large (Ke Jie was leading about 12 points before komi in the end, which is a rather big margin in pro game.). I did not mean that the game was completely one-sided.

Now some technical analysis:

Click Here To Show Diagram Code

[go]$$
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . X O . O O O . O . . . . . . . . . |
$$ | . . X O O X X X X , . . . . . , X . . |
$$ | . . X O X . . . . . . . . . . . . . . |
$$ | . . X X X . . . . . . . . . . . . . . |
$$ | . . O . . . . . X . . . . . . . . . . |
$$ | . . . . . O O X . X . . . . . . . . . |
$$ | . . O 0 O X O . X O . . . . . . O . . |
$$ | . X X O 7 X O . O a . . . . . , . . . |
$$ | . X O X 2 X 9 O . b . . . . . . . . . |
$$ | . . . 3 6 8 X O . X 1 . . . . . . . . |
$$ | . . X . . . X O X . O . . . . O O . . |
$$ | . . X O O 4 5 X O . . . . . X X X O . |
$$ | . . O X . . X . . . . . . . . . O X . |
$$ | . . O , . O X . . O . . . O X , X . . |
$$ | . . . O . O . X . O . . . O . X . . . |
$$ | . . . . . . . . X O . . . . X . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

White can indeed cut black this way (note that is the correct answer). However, if white plays this immediately, black could cut at 'a' and capturing race is not good for white (according to some pro analysis).

Click Here To Show Diagram Code

[go]$$
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . X O . O O O . O . . . . . . . . . |
$$ | . . X O O X X X X , . . . . . , X . . |
$$ | . . X O X . . . . . . . . . . . . . . |
$$ | . . X X X . . . . . . . . . . . . . . |
$$ | . . O . . . . . X . . . . . . . . . . |
$$ | . . . . . O O X . X . . . . . . . . . |
$$ | . . O . O X O . X O . . . . . . O . . |
$$ | . X X O . X O . O , . . . . . , . . . |
$$ | . X O X . X . O . . . 2 . . . . . . . |
$$ | . . . . . . X O . X 1 3 . . . . . . . |
$$ | . . X . . . X O X . O . . . . O O . . |
$$ | . . X O O . . X O . . . . . X X X O . |
$$ | . . O X . . X . . . . . . . . . O X . |
$$ | . . O , . O X . . O . . . O X , X . . |
$$ | . . . O . O . X . O . . . O . X . . . |
$$ | . . . . . . . . X O . . . . X . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Lee Sedol's was indeed a very smart move. If black plays the obvious , white can then carry out the plan in the previous diagram, and white can run out from 'b' in the previous diagram. So black cannot play here.

Click Here To Show Diagram Code

[go]$$
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . X O . O O O . O . . . . . . . . . |
$$ | . . X O O X X X X , . . . . . , X . . |
$$ | . . X O X . . . . . . . . . . . . . . |
$$ | . . X X X . . . . . . . . . . . . . . |
$$ | . . O . a 3 . . X . . . . . . . . . . |
$$ | . . . . 1 O O X . X . . . . . . . . . |
$$ | . . O . O X O . X O . . . . . . O . . |
$$ | . X X O b X O . O , . . . . . , . . . |
$$ | . X O X . X . O . . . O . . . . . . . |
$$ | . . . . . . X O . B B 2 . . . . . . . |
$$ | . . X . . . X O B . O . . . . O O . . |
$$ | . . X O O . . X O . . . . . X X X O . |
$$ | . . O X . . X . . . . . . . . . O X . |
$$ | . . O , . O X . . O . . . O X , X . . |
$$ | . . . O . O . X . O . . . O . X . . . |
$$ | . . . . . . . . X O . . . . X . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Black played here instead. White could not play 'a' to capture - if doing so 'b' would become a sente move for black so white could not longer play the sequence in the first diagram. So the exchange in the real game was the only way for both sides.

Looking at the outcome, it is easy to feel good for white. After all white was under attack earlier and now he not only managed to save his weak group but also captured three stones.

Click Here To Show Diagram Code

[go]$$
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . X O . O O O . O . . . . . . . . . |
$$ | . . X O O X X X X , . . . . . , X . . |
$$ | . . X O X . . . . . . . . . . . . . . |
$$ | S S X X X . . . . . . . . . . . . . . |
$$ | S S @ S S X a . X . . . . . . . . . . |
$$ | S S S S X O O X . X . . . . . . . . . |
$$ | S S @ S @ X O . X O . . . . . . O . . |
$$ | S X X @ . X O . O , b . . . . , . . . |
$$ | . X O X . X . O . . . O . . . . . . . |
$$ | . . . . . . X O . X X O . . . . . . . |
$$ | . . X . . . X O X . O . . . . O O . . |
$$ | . . X O O . . X O . . . . . X X X O . |
$$ | . . O X . . X . . . . . . . . . O X . |
$$ | . . O , . O X . . O . . . O X , X . . |
$$ | . . . O . O . X . O . . . O . X . . . |
$$ | . . . . . . . . X O . . . . X . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

However, in my opinion the exchange was not a failure from black's perspective. Black got many points as marked in the diagram: 22 points, plus the extra 7+ point if getting 'a' later. White only captured 3 stones, with aji at 'b' (which means white needed to mend it immediately in the real game, leaving black a sente). White also got some extra thickness which is hard to quantify (but not cash value at the moment). So overall, in terms of points, black was really not bad after the exchange.

Click Here To Show Diagram Code

[go]$$B
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . X O . O O O . O . . . . . . . . . |
$$ | . . X O O X X X X , . . . . . , X . . |
$$ | . . X O X . . . . . . . . . . . . . . |
$$ | . . . X X . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . . 1 . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . O O . . |
$$ | . . X O O . . . . . . . . . X X X O . |
$$ | . . O X . . # . . . . . . . . . O X . |
$$ | . . O , . O # . . O . . . O X , X . . |
$$ | . . . O . O . # . O . . . O . X . . . |
$$ | . . . . . . . . . . . . . . a . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ +---------------------------------------+
$$ {AR F13 F9}[/go]

This is the position before white's invasion. Please compare this with the above diagram. Black secured all points below the 6th line. Black also got the three marked stones home safely. Black even somehow got the large yose at 'a'. The only price paid was the three stones in the middle.

Yup.



I agree that the exchange might not be a total failure, but the point is it means that black's move here was a mistake that white punished:

Click Here To Show Diagram Code

[go]$$
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . X O . O O O . O . . . . . . . . . |
$$ | . . X O O X X X X , . . . . . , X . . |
$$ | . . X O X . . . . . . . . . . . . . . |
$$ | . . X X X . . . . . . . . . . . . . . |
$$ | . . O . . . . . X . . . . . . . . . . |
$$ | . . . . . O O X . X . . . . . . . . . |
$$ | . . O . O X O . X O . . . . . . O . . |
$$ | . X X O . X O . O , . . . . . , . . . |
$$ | . X O X . X . O . . . . . . . . . . . |
$$ | . . . . . . X O . X B . . . . . . . . |
$$ | . . X . . . X O X . O . . . . O O . . |
$$ | . . X O O . . X O . . . . . X X X O . |
$$ | . . O X . . X . . . . . . . . . O X . |
$$ | . . O , . O X . . O . . . O X , X . . |
$$ | . . . O . O . X . O . . . O . X . . . |
$$ | . . . . . . . . X O . . . . X . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

There is no reason to play this move if Ke Jie had anticipated white's next move.

That's why I didn't think it was fair to say that the game was entirely comfortable for Ke Jie. Maybe it's not what you meant, now that you clarified that you were talking about the endgame score difference.



Plus the thickness white got. (Also, black should be expected to get a lot of points in an area where he has a large moyo like that.)

---

Anyway, I pretty much agree with the thoughts from your analysis (even before you posted it). I'm simply saying that I think that Lee Sedol still had a pretty good chance after capturing the three stones. The thickness he got was hard to quantify, I agree, but I wouldn't say that the game is comfortable for either side at that particular point. (Again, maybe this is not what you meant, after your clarification.)

After the stuff in the top right, I would say the game became more comfortable for Ke Jie, and it became harder and harder for white to find a chance to win (especially after the monkey jump on the bottom).

_________________
be immersed