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Opening problems for AI: Problem 11
http://www.lifein19x19.com/viewtopic.php?f=15&t=17585
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Author:  Bill Spight [ Mon Jun 22, 2020 8:57 pm ]
Post subject:  Opening problems for AI: Problem 11

Another game between Takagawa (W) and Sakata, GoGoD 1954-09-08a.

Click Here To Show Diagram Code
[go]$$Wcm28 White to play
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . O . . . . . . . O . O O O . |
$$ | . . . X . . . . . , . . . . X X O X . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . X . . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . . X . . . . . , . . . O . , X . . |
$$ | . . . . . O . . . O . . . . . O X . . |
$$ | . . . . . . . . . . . . . . . . O X . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Takagawa made a textbook play, but Elf reckons that it loses 16% to par.

Author:  Bill Spight [ Mon Jun 22, 2020 9:00 pm ]
Post subject:  Re: Opening problems for AI: Problem 11

No surprise, Boshi no Takagawa played a boshi on the left side.

Click Here To Show Diagram Code
[go]$$Wcm28 Boshi, game continuation
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . 2 . . . . . . . . . . . . . . . |
$$ | . . . . . O . . . . . . . O . O O O . |
$$ | . . . X . . . . . , . . . . X X O X . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . X . . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . 3 . . . . . . . . . . . . . . . . |
$$ | . . B , 1 . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . . X . . . . . , . . . O . , X . . |
$$ | . . . . . O . . . O . . . . . O X . . |
$$ | . . . . . . . . . . . . . . . . O X . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

:b29: secured the top left corner, and then :w30: attaches against :bc: to invade the left side.


Click Here To Show Diagram Code
[go]$$Bcm29 Elf's mainline variation for :b29:
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . 1 O . . . . . . 8 O . O O O . |
$$ | . . . X . 2 . . 5 , . . . 7 X X O X . |
$$ | . . . . . . . . . . . . 3 . . . X . . |
$$ | . . . X . . . . . . . . . . 6 X . . . |
$$ | . . . . . . . . . . . . 9 . 4 . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . 0 . . . . . |
$$ | . . X , O . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . . X . . . . . , . . . O . , X . . |
$$ | . . . . . O . . . O . . . . . O X . . |
$$ | . . . . . . . . . . . . . . . . O X . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

After the kick, :b29:, and :w30:, :b31: bolsters the Black group in the top right and aims at the pincer, :b33:. :w32: starts an attack against the Black group. :b37: plays on the frontier of the incipient moyos, expanding the Black moyo and limiting the expansion of the White moyo. With sente, nonetheless.

Click Here To Show Diagram Code
[go]$$Wcm28 Elf variation for :w28:
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . O . . . . . . . O . O O O . |
$$ | . . . X . . . . . , . . . . X X O X . |
$$ | . . . . 3 . . . . . . . 2 . . . X . . |
$$ | . . . X . . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . 1 . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . . X . . . . . , . . . O . , X . . |
$$ | . . . . . O . . . O . . . . . O X . . |
$$ | . . . . . . . . . . . . . . . . O X . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

:w28: attacks the Black group. If :b29:, White switches to the top left corner with :w30:p


Click Here To Show Diagram Code
[go]$$Bcm29 Variation 2, mainline
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . 1 O . . . . . . 4 O . O O O . |
$$ | . . . X . . . . . , . . . 3 X X O X . |
$$ | . . . . . . . . . . 7 . 5 . . . X . . |
$$ | . . . X . . . . . . . . . . 2 X . 9 . |
$$ | . . . . . . . . . . 8 . 6 . O . 0 . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . . X . . . . . , . . . O . , X . . |
$$ | . . . . . O . . . O . . . . . O X . . |
$$ | . . . . . . . . . . . . . . . . O X . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

In the mainline variation :b29: plays the kick in the top left, then White presses the attack against the Black group. As a result White builds a moyo into the center. Elf regards this attack as more urgent than the boshi on the left side.

Elf regarded the top right as urgent earlier. Sakata played :b23: at a in the next diagram, but Elf recommends making a wall on the right.

Click Here To Show Diagram Code
[go]$$Bcm23 Mainline for :b23:
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . O . O O O . |
$$ | . . . X . . . . . , . . . . X X O X . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . 3 O . . |
$$ | . . . . . . . . . . . . . . . 1 2 . . |
$$ | . . a , . . . . . , . . . . 5 4 . . . |
$$ | . . . . . . . . . . . . . . . 6 . . . |
$$ | . . . . . . . . . . . . . . . O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . . X . . . . . , . . . O . , X . . |
$$ | . . . . . . . . . O . . . . . O X . . |
$$ | . . . . . . . . . . . . . . . . O X . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Author:  dhu163 [ Fri Jun 04, 2021 10:06 am ]
Post subject:  Re: Opening problems for AI: Problem 11

Speculatively:
Current position:
1. Right side seems hot, but I can't see a good move for W to defend. P12 might be slack. P6 too will lose territory when later B R7.
2. C17 seems natural to settle.
3. E15, E5 very natural but as B has support, B can fight back with E3/E17. Hence, its tempting to probe around E12 first. D10 is shapey later but I don't see any weak B group to fight against. Still E15/E5 very natural anyway. On the other hand W can't easily make a big area on upper side or lower side as B has groups on the edges of it (in all 4 corners) and W can only thinly shut them off.
4. W might have a moyo on the lower side, but this seems to require P6 first.
5. O16 shapey, but too damaging to right side.
6. P2 a move sometimes, hard to judge.
7. Overall I am tempted by P6 with E15 second.

Opp to play
1. E17 E16 H17 attack.
2. O4 get out, cut off weak group
3. N15 defend weak group, reduce top.

Past:
1. Seems pretty balanced, B's shape on left is ok, B has advantage in 3 corners, but the S16 S17 exchange is terrible.

Check:
1. I missed the key point at P13, probably due to not daring to play such a tight move.

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