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Opening problems for AI: Problem 10
http://www.lifein19x19.com/viewtopic.php?f=15&t=17582
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Author:  Bill Spight [ Sun Jun 21, 2020 3:47 pm ]
Post subject:  Opening problems for AI: Problem 10

Many thanks to Dave (ez4u) for pointing out this position from the first game of the 9th Honinbo final match, GoGoD 1954-05-16a, between Sugiuchi Masao, 7 dan, (W) and Takagawa Shukaku, 8 dan, Honinbo.

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

In the game in 1953 for Problem 8, Takagawa had played the low extension in the joseki in the bottom right in this game, and Sakata had later played a boshi against that stone. In this game Takagawa played the high extension, :bc:.

As I recall, the next play, :w12:, was praised by Sakata in a similar position in one of his writings, but Elf reckons that it loses a whopping 24% to par.

Author:  Bill Spight [ Sun Jun 21, 2020 4:24 pm ]
Post subject:  Re: Opening problems for AI: Problem 10

Click Here To Show Diagram Code
[go]$$Wcm12 Special splitting move
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . c a 1 b . . . . . . . |
$$ | . . . X . . . . . , . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . X X . . |
$$ | . . O . . . . . . . . . . . . X O . . |
$$ | . . . , . . . . . , . . . . O , O . . |
$$ | . . . . . . . . . . . . . . . O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Sakata praised :w12: in a similar position for being one space closer to the Black moyo than a, thus hindering Black from expanding the moyo with a play at b. Takagawa in this game played :b13: at c, which Elf docks by 13½%.


Click Here To Show Diagram Code
[go]$$Bcm13 Elf's mainline variation for :b13:
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . O . . . . . . . . |
$$ | . . . X . . . . . , . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . X X . . |
$$ | . . O 4 . . . . . . . . . . . X O . . |
$$ | . . . 3 2 6 8 0 . , . . . . O , O . . |
$$ | . . 1 . 5 7 9 . . . . . . . . O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

:b13: invades the bottom left corner on the 3-3


Click Here To Show Diagram Code
[go]$$Bcm23 Elf's mainline variation for :b13:, continued
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . W . . 9 . . . . . |
$$ | . . . X . . . . . , . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . X X 7 . |
$$ | . . O O . . . . . . . . . . . X O . . |
$$ | . . . X O O O O . , . . . . O 1 O 8 . |
$$ | . . X . X X X . . . . . . . 2 O 3 4 . |
$$ | . . . . . . . . . . . . . . . . 5 6 . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

:b23: - :w30: shows Black's kikashi against the bottom right corner. Next, :b31: encloses the top right corner and threatens to pincer the :wc: stone.

Click Here To Show Diagram Code
[go]$$Wcm12 Enclose the bottom left corner
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . 9 . . . . . . . . . . . . . |
$$ | . . 3 5 7 6 . . . . . . . 2 . . . . . |
$$ | . . 4 X 8 . . . . a . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . X X . . |
$$ | . . O . . . . . . . . . . . . X O . . |
$$ | . . . , . . . . . , . . . . O , O . . |
$$ | . . . 1 . . . . . . . . . . . O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Elf's top choice for :w12: is to enclose the bottom left corner. Then the main line is for Black to enclose the top right corner instead of playing yonrensei at a. Next, :w14: invades the top left corner.


Click Here To Show Diagram Code
[go]$$Bcm21 Mainline for :w12:, continued
$$ ---------------------------------------
$$ | . . . 7 . . . . . . . . . . . . . . . |
$$ | . . 5 6 8 O . 4 . . . . . . . . . . . |
$$ | . 1 O O O X 2 . . . . . . X . . . . . |
$$ | . . X X X 3 . . . , . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . 9 . . . . . . . . . . . X X . . |
$$ | . . O . . . . . . . . . . . . X O . . |
$$ | . . . , . . . . . , . . . . O , O . . |
$$ | . . . O . . . . . . . . . . . O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

:w22: - :w24: moves into the top side rather than let it become Black territory or moyo. :b29: takes sente and plays a shoulder blow against the bottom left corner.

Author:  dhu163 [ Fri Jun 04, 2021 10:03 am ]
Post subject:  Re: Opening problems for AI: Problem 10

Speculatively:
Current position:
1. As usual, shimari D3.
2. Otherwise I find it hard to choose between O17 and C17. O17 is normal with shape on right making a balance between reducing right and occupying living space on upper side (which is also B's development potential). R17 seems less common as B resulting wall is already defended by Q10, and B's moyo becomes very big.

Opp to play
1. C3/D3

Past:
1. Lower right means B probably slightly ahead

Check:
1. too simple

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