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 Post subject: Gobsmacking move
Post #1 Posted: Mon Jul 31, 2017 2:56 am 
Oza

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This position gobsmacked me this morning - I assumed the next move was a misprint - and then amused me for two reasons.



White (Takenaka Kotaro) to play on the lower side. Where?



I had assumed the triangled cut was the only move, as did Black (Kuroda Yukio) who said he planned to play A next. But - my first chuckle - he said he too was "gobsmacked" when he saw what White played, as follows:



This momentum-denying move is surprisingly effective, especially bearing in mind he has to try to counter Black's sanrensei influence on the right. The game continued in predictable enough fashion to reach the position shown below, where White sanguinely let Black live by cutting off three stones - my second (wry) chuckle given a concurrent thread which involved a debatable capture of three stones.



White went on to win this game rather soon, and his outside wall certainly looks impressive. But it's an interesting question as to how it compares with Black's structure on the right, which is obviously wide open but is backed by the edges of the board.

The sword-wielding method of estimation for White doesn't seem to apply here as there is no obvious extension, so if we instead use the "three points per wall stone" heuristic (which I find slightly optimistic) we get a White value of at least a bit over 40 points. Let us assume the Black stone at the top is cancelled out not just by White's thickness but by White's obvious lead on the left side. We can then estimate Black's moyo very simply by the virtual territory method (i.e. he gets half and White decimates the other half). That looks like something in the region of only 30 points (not to mention at least a couple of points wherever White lives there - no komi, though).

Any other views on the comparison?

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 Post subject: Re: Gobsmacking move
Post #2 Posted: Mon Jul 31, 2017 6:49 am 
Gosei

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It is a nice looking move. I gave some thought to the clamp, the direct cut, and the peep, I even briefly considered a keima, but I didn't reach any conclusion as to which was best. What puzzles me the most is why Black did not continue as he originally planned when he was surprised by this clever move. Why did it suddenly become bad?

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 Post subject: Re: Gobsmacking move
Post #3 Posted: Mon Aug 07, 2017 12:07 am 
Lives in gote
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Javaness2 wrote:
It is a nice looking move. I gave some thought to the clamp, the direct cut, and the peep, I even briefly considered a keima, but I didn't reach any conclusion as to which was best. What puzzles me the most is why Black did not continue as he originally planned when he was surprised by this clever move. Why did it suddenly become bad?


My rudimentary analysis is Black playing A after the expected move threatens a double atari that White must handle.

After white's nobi, Black playing H6 could be comfortably met with White J6 and White still has a clear path upwards in to the middle whereas Black's H6 accomplishes basically nothing.

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 Post subject: Re: Gobsmacking move
Post #4 Posted: Mon Aug 07, 2017 1:52 am 
Judan

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It reminds me of white 14 in the joseki below: You could cut but then you get squeezed horribly (black might sacrifice the 3 stones and get nice outside, or connect under and fight) so it's actually better to peep where you can cut (against the proverb) and make a strong shape and force the opponent to make a painful connection (though in this game that would be heavy so black runs out, meaning white has the cut as an emergency connection should he ever need it).

Click Here To Show Diagram Code
[go]$$B
$$ , . . . . . , . . . |
$$ . . . . . . . . . . |
$$ . . . . . . 9 . 0 . |
$$ . . . . . . . . . . |
$$ . . . . . 7 . 8 . . |
$$ . . . . . 3 2 . . . |
$$ , . . . . . 5 6 . . |
$$ . . . . . . 1 4 . . |
$$ . . . . . . . . . . |
$$ . . . . . . . . . . |
$$ --------------------+[/go]


Click Here To Show Diagram Code
[go]$$Bm11
$$ 1 . . . . . , . . . |
$$ . . . . . . . . . . |
$$ . . . . . . X . O . |
$$ . . . . . . . . . . |
$$ . . . . . X . O . . |
$$ . . . . . X O . . . |
$$ , . . . 4 . X O . . |
$$ . . . . 2 . X O . . |
$$ . . . . . . 3 . . . |
$$ . . . . . . . . . . |
$$ --------------------+[/go]

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