The game is GoGoD 1660+v, Honinbo Dosaku (W) vs. Masaki Kasue.
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[go]$$Bcm39 Anti-suji
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$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O X . . . . . . . . . . . . . . |
$$ | . O X O X . . . . . . . X . . X . . . |
$$ | . O X , X . . . . , . . . . . , . . . |
$$ | . . O X X . . . . . . . . . . . O . . |
$$ | . . O O X . . . . . . . . . . . . . . |
$$ | . . . . O O . . . . . . . . . . 3 . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . a . . |
$$ | . . X . . . . . . . . . . O . . 2 . . |
$$ | . . . . . . . . . . . . . X O O . . . |
$$ | . . . . . . . . . . . . . . X X O . . |
$$ | . . X , . . . . . , . . . . . 1 O . . |
$$ | . . . . O . . . . O . X . . . X X O . |
$$ | . . . . . . . . . . . . . . . . . X . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
Masaki played the anti-suji,
, threatening to cut. Elf reckons that this play loses 31% to par. It is one of those plays that strengthens your opponent. I did not expect it to attract any votes.
Dosaku protected against the cut with
. Then Masaki played the one space pincer in the top right corner.
Elf prefers
a to
by 2%.
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[go]$$Bcm39 Variation for
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$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O X . . . . . . . . . . . . . . |
$$ | . O X O X . . . . . . . X . . X . . . |
$$ | . O X , X . . . . , . . . . . , . . . |
$$ | . . O X X . . . . . . . . . 4 . O . . |
$$ | . . O O X . . . . . . . . . . . . . . |
$$ | . . . . O O . . . . . . . . . . 3 . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . 2 . . |
$$ | . . X . . . . . . . . . . O . . . . . |
$$ | . . . . . . . . . . . . . X O O . . . |
$$ | . . . . . . . . . . . . . . X X O . . |
$$ | . . X , . . . . . , . . . . . 1 O . . |
$$ | . . . . O . . . . O . X . . . X X O . |
$$ | . . . . . . . . . . . . . . . . . X . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
plays the pincer, as above, and
jumps out.
The "only move"
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[go]$$Bcm39 Central two step hane
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O X . . . . . . . . . . . . . . |
$$ | . O X O X . . . . . . . X . . X . . . |
$$ | . O X , X . . . . , . . . . . , . . . |
$$ | . . O X X . . . . . . . . . . . O . . |
$$ | . . O O X . . . . . . . . . . . . . . |
$$ | . . . . O O . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . a . . |
$$ | . . . . . . . . . . . . . . . b . . . |
$$ | . . O , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . d . . |
$$ | . . . . . . . . . . . . 4 2 . . . . . |
$$ | . . X . . . . . . . . . 1 O . . . . . |
$$ | . . . c . . . . . . . . 3 X O O . . . |
$$ | . . . . . . . . . . . . . . X X O . . |
$$ | . . X , . . . . . , . f e . . . O . . |
$$ | . . . . O . . . . O . X . . . X X O . |
$$ | . . . . . . . . . . . . . . . . . X . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
Elf greatly prefers the two step hane, with 98.4k rollouts. No other choice gets any mention in the commentary. No other play compares, as pwaldron says.
I chose this position not only as an only move problem, but also because it illustrates AI play in the center, where I feel that it is head and shoulders above human play.
Still, as Knotwilg indicates, it induces two good plays by White, the 6th line (!) extension by White and the central turn,
. Elf greatly prefers
, giving it 88.3k rollouts. Other moves,
a -
e, in order of preference, are possible, perhaps even playable, but the second choice,
a, gets only 4k rollouts. If White plays at
e, Black replies at
f.
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[go]$$Wc Kikasare
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$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O X . . . . . . . . . . . . . . |
$$ | . O X O X . . . . . . . X . . X . . . |
$$ | . O X , X . . . . , . . . . . , . . . |
$$ | . . O X X . . . . . . . . . . . O . . |
$$ | . . O O X . . . . . . . . . . . . . . |
$$ | . . . . O O . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . a O . . . . . |
$$ | . . . . . . . . . . . . 1 X O O . . . |
$$ | . . . . . . . . . . . . . 2 X X O . . |
$$ | . . X , . . . . . , . . . . . . O . . |
$$ | . . . . O . . . . O . X . . . X X O . |
$$ | . . . . . . . . . . . . . . . . . X . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
FWIW, my own feeling is that White's threat, the atari,
, is too painful. And if Black extends to
1 instead of the two step hane, White can reply at
a.
Back to the mainline variation.
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[go]$$Bcm39 Mainline variation
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O X . . . . . . . . . . . . . . |
$$ | . O X O X . . . . . . . X . . X . . . |
$$ | . O X , X . . . . , . . . . . , . . . |
$$ | . . O X X . . . . . . . . . . . O . . |
$$ | . . O O X . . . . . . . . . . . . . . |
$$ | . . . . O O . . . . . . . . . . 5 0 . |
$$ | . . . . . . . . . . . . . . . 9 8 . . |
$$ | . . . . . . . . . . . . . . . 7 6 . . |
$$ | . . O , . . . . . , . . . . . , a . . |
$$ | . . . . . . . . . . . . . . . . c . . |
$$ | . . . . . . . . . . . . 4 2 . . . . . |
$$ | . . X . . . . . . . . d 1 O . . . . . |
$$ | . . . . . . . . . . . . 3 X O O . . . |
$$ | . . . . . . . . . . . . . . X X O . . |
$$ | . . X , . . . . . , . . b . . . O . . |
$$ | . . . . O . . . . O . X . . . X X O . |
$$ | . . . . . . . . . . . . . . . . . X . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
plays the one space pincer. With the support of
and
,
threatens to make a goodly territory in the right side.
a -
d are also possible After the top attachment of
, White crawls and connects underneath, making territory that way.
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[go]$$Bcm49 Mainline variation, continued
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$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O X . . . . . . . . . . . . . . |
$$ | . O X O X . . . . . . . X . . X . . . |
$$ | . O X , X . . . . , . . . . . , . . . |
$$ | . . O X X . . . . . . . . . . 5 O . . |
$$ | . . O O X . . . . . . . . . . . . 2 . |
$$ | . . . . O O . . . . . . . . . 1 X O . |
$$ | . . . . . . . . . . . . . . . X O . . |
$$ | . . . . . . . . . . . . . . . X O . . |
$$ | . . O , . . . . . , . . . . . 3 4 . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . O O . . . . . |
$$ | . . X . . . . . . . . . X O . . . . . |
$$ | . . . . . . . . . . . . X X O O . . . |
$$ | . . . . . . . . . . . . . . X X O . . |
$$ | . . X , . . . . . , . . . . . . O . . |
$$ | . . . . O . . . . O . X . . . X X O . |
$$ | . . . . . . . . . . . . . . . . . X . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
After White connects,
intrudes once into White's territorial framework with sente, and the comes back and stablizes Black's wall.