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Opening problems for AI: Problem 14
http://www.lifein19x19.com/viewtopic.php?f=15&t=17593
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Author:  Bill Spight [ Fri Jun 26, 2020 10:53 am ]
Post subject:  Opening problems for AI: Problem 14

Todays's position is from GoGoD 1992-11-17a, the 2d Ing Cup semi-final, game3, between Otake Hideo (W) and Rui Naiwei. Otake made a fine move for the time, but Elf reckons that it lost 13% to par.

Click Here To Show Diagram Code
[go]$$Wcm12 White to play
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . O . . . O . . . . . . . . . . |
$$ | . . X , . . . . . , . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . . . X O . . |
$$ | . . . X . . . . . , . . . . . , O . . |
$$ | . . . . . . . . . . . . . . . O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Author:  Bill Spight [ Fri Jun 26, 2020 10:54 am ]
Post subject:  Re: Opening problems for AI: Problem 14

Click Here To Show Diagram Code
[go]$$Wcm12 Pincer, then mainline variation
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . O . . . O . . . . a . . . . . |
$$ | . . X , . . . . . , . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . B . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . 4 . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . 1 . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . 2 X . . |
$$ | . . . . . . . . . . . . . . . X O . . |
$$ | . . . X . . . . . , . . . . . , O . . |
$$ | . . . . . 5 . . . . . . . 3 . O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Otake played the pincer, :w12:. Then Elf recommends the solid connection, :b13:. :w14: extends on the bottom side, and then :b15: plays a counterpincer. From the pre-AI perspective, White can be satisfied to have prevented Black from making an ideal extension on the right side, and :w16: plays elsewhere.

However, the bots do not consider that extension to be ideal, and often omit it. In this case, instead of :b11: at :bc:, Elf's choice is :b13: and after White extends to :w14:, for Black to make the enclosure at a instead of extending on the right side.

Click Here To Show Diagram Code
[go]$$Wcm12 Cut, mainline variation
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . 9 . . . . |
$$ | . . . . O . . . O . . . . . . . 7 . . |
$$ | . . X , . . . . . , . . . . . X 5 . . |
$$ | . . . . . . . . . . . . . . . 8 6 . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . 4 . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . 2 . . |
$$ | . . . . . . . . . . . . . . 3 1 X . . |
$$ | . . . . . . . . . . . . . . . X O . . |
$$ | . . . X . . . . . , . . . . . , O . . |
$$ | . . . . . . . . . . . . . . . O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Elf prefers the cut. Then :b13: pulls back and :w14: stands. After :b15:, :w16: attaches at R-16 instead of invading at R-17, presumably to prevent Black from blocking that invasion at R-17. I expect that the White extension on the top side is one reason for that decision.

Author:  Uberdude [ Fri Jun 26, 2020 11:43 am ]
Post subject:  Re: Opening problems for AI: Problem 14

Don't know what Otake would play, but expect Elf says he should have cut.

Author:  dhu163 [ Fri Jun 04, 2021 10:10 am ]
Post subject:  Re: Opening problems for AI: Problem 14

Speculatively:
Current position:
1. It's well-known now that Q6 is bigger than normal. The W corner gets very thick and this helps create follow ups on both sides that B finds it hard to remove with just one move. It is like the Q3 Q6 shimari except B has made some bad exchanges, removing its main weakness.
2. Otherwise either 3-3 is natural.

Opp to play
1. Connect Q6

Past:
1. B shouldn't have let W get Q6, so W should be ahead. D14 seems early for its time given that we call it an AI move and J17 seems premature.

Check:
1. close in some places

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