Position from Pro Game; why did W play this way?

[zac]

I've been playing through a lot of Lee Changho's games lately, not really studying them, just playing through for enjoyment. But the following position grabbed my attention. The game is the 21st Myeogin semi-final, Lee Changho is Black, and Seo Bongsoo is White. Black to play;



Is it not possible for white to get a Seki from here? In the game, B played F2, W played a hane at G1, which allowed Lee to live outright.

The full game is here; http://www.go4go.net/go/games/sgfview/59668

My immediate thought it that Lee seems to have a considerable lead, is Seo hoping for a mistake, and when Lee doesn't make it he resigns? Does anyone have any further insight in to the game?

All the best,

Zac

[John Fairbairn]

My suspicion is that Seo misread and missed that Black has a capture on the outside when White tries the under-the-stones. Seo has occasionally been guilty of such blunders.

But the Korean commentary makes no comment about this (it ends at move 62, the point at which White went off the rails). There is a possibility the score was corrupt because the Korean Yearbook says 156 moves, B+R (but does only show 155) and around that time the printing mistakes were rife in Korean yearbooks.

[HermanHiddema]

White has a number of options here.

White can make seki in gote:

$$B
$$ | . . . . . . . . . . .
$$ | . . . . . . . O . O .
$$ | . . . . . . O . . . .
$$ | . O . O O O . X O O .
$$ | . . O X 4 X X X X O .
$$ | . O X X 5 1 . X O . .
$$ | . . X . O 6 2 3 . O .
$$ +----------------------

Click Here To Show Diagram Code

[go]$$B
$$ | . . . . . . . . . . .
$$ | . . . . . . . O . O .
$$ | . . . . . . O . . . .
$$ | . O . O O O . X O O .
$$ | . . O X 4 X X X X O .
$$ | . O X X 5 1 . X O . .
$$ | . . X . O 6 2 3 . O .
$$ +----------------------[/go]

Or reduce black to 5 points in sente:

$$B
$$ | . . . . . . . . . . .
$$ | . . . . . . . O . O .
$$ | . . . . . . O . . . .
$$ | . O . O O O . X O O .
$$ | . . O X . X X X X O .
$$ | . O X X 5 1 . X O . .
$$ | . . X . O . 3 2 4 O .
$$ +----------------------

Click Here To Show Diagram Code

[go]$$B
$$ | . . . . . . . . . . .
$$ | . . . . . . . O . O .
$$ | . . . . . . O . . . .
$$ | . O . O O O . X O O .
$$ | . . O X . X X X X O .
$$ | . O X X 5 1 . X O . .
$$ | . . X . O . 3 2 4 O .
$$ +----------------------[/go]

It may seem like there is ko:

$$B
$$ | . . . . . . . . . . .
$$ | . . . . . . . O . O .
$$ | . . . . . . O . . . .
$$ | . O . O O O . X O O .
$$ | . . O X . X X X X O .
$$ | . O X X . 1 . X O . .
$$ | . . X . O 4 3 2 . O .
$$ +----------------------

Click Here To Show Diagram Code

[go]$$B
$$ | . . . . . . . . . . .
$$ | . . . . . . . O . O .
$$ | . . . . . . O . . . .
$$ | . O . O O O . X O O .
$$ | . . O X . X X X X O .
$$ | . O X X . 1 . X O . .
$$ | . . X . O 4 3 2 . O .
$$ +----------------------[/go]

But black can play like this:

$$Bm5 :w6: captures the stone at the marked point.
$$ | . . . . . . . . . . .
$$ | . . . . . . . O . O .
$$ | . . . . . . O . . . .
$$ | . O . O O O . X O O .
$$ | . . O X . X X X X O .
$$ | . O X X 1 X 2 X O . .
$$ | . . X 3 O O C O . O .
$$ +----------------------

Click Here To Show Diagram Code

[go]$$Bm5 :w6: captures the stone at the marked point.
$$ | . . . . . . . . . . .
$$ | . . . . . . . O . O .
$$ | . . . . . . O . . . .
$$ | . O . O O O . X O O .
$$ | . . O X . X X X X O .
$$ | . O X X 1 X 2 X O . .
$$ | . . X 3 O O C O . O .
$$ +----------------------[/go]

And white can't play the under the stones that John mentions:

$$Wm8
$$ | . . . . . . . . . . .
$$ | . . . . . . . O . O .
$$ | . . . . . . O . . . .
$$ | . O . O O O . X O O .
$$ | . . O X . X X X X O .
$$ | . O X X X X O X O . .
$$ | . . X X O O 1 O 2 O .
$$ +----------------------

Click Here To Show Diagram Code

[go]$$Wm8
$$ | . . . . . . . . . . .
$$ | . . . . . . . O . O .
$$ | . . . . . . O . . . .
$$ | . O . O O O . X O O .
$$ | . . O X . X X X X O .
$$ | . O X X X X O X O . .
$$ | . . X X O O 1 O 2 O .
$$ +----------------------[/go]

because after you're in atari and can't play the vital point.

[Uberdude]

Terminology question: does this count as "under the stones"? I thought not, as I thought that meant when the opponent captures some stones and you then play inside and capture the capturing stones back (probably the first plural is important there as I don't think a common snapback counts). If that stricter meaning isn't used then wouldn't a humdrum nakade on the vital point after your opponent captured a bulky five also count as an under the stones? I thought it was reserved for fancy-looking rare occurrences (which I tried to quickly define above but maybe there's some imprecision).

[John Fairbairn]

You may recall that I distinguished two types of under-the-stones in GTAM, so you are right to observe a difference. But the guiding principle for using the term (especially if we look at the various names appended in the ancient Chinese example) appears to be the element of surprise the manoeuvre can elicit. For example it was likened to Daoist metamorphosis, and that kind of metaphor was used of the commonest cases where apparently dead stones come back to life by changing their form (i.e. their flesh and bones). But there are examples where the result is a ko or a kill.

As you point out, a nakade is humdrum. Once the bulky X is made the group is a Polly Parrot group: it is no more, it has ceased to be, it is bereft of life, it rests in peace, this is an ex-group.

But with groups such as here, although there is a bulky X it is not a standard dead shape and so the eventual psittacide has an element of surprise.

[macelee]

Would it be helpful if black connects at K2 instead of K1? Does that change the outcome?

[zac]

Thank you all for your replies.
The variations HermanHiddema posted was what I had read out, but not recognising that without the problem of the atari, an under-the-stones would have been possible. Interesting that this should come up after the recent discussion of that tesuji.
Usually when re-playing games I don't try much to understand, just enjoy the game and get a bit of a feeling for the flow, direction, big points etc, but this one had me really scratching my head. The thought that it was a mistake by Seo did briefly cross my mind, but it seemed too simple a mistake for a 9D pro to make.
From memory I've only seen a couple of his games, so it's nice to get a bit of a back-story r.e. his making blunders. This is another enjoyable aspect to playing through the games; learning more about the players, the tournaments etc.


Thanks again,

Zac

PS John, what is GTAM?

[Uberdude]

Would it be helpful if black connects at K2 instead of K1? Does that change the outcome?

Then in Herman's diagram 3 Black 5 would just capture 2 (rather than squeezing to avoid ko), no?

GTAM = Gateway to all marvels, a classic Chinese problem collection aka Xuanxuan Qijing. John made an ebook version with commentary.

[macelee]

Would it be helpful if black connects at K2 instead of K1? Does that change the outcome?

Then in Herman's diagram 3 Black 5 would just capture 2 (rather than squeezing to avoid ko), no?

Yes you are right!

[Bill Spight]

Never mind.