Game 18
Iwamoto Kaoru (W) vs. Fujisawa Kuransuke, Honibo League, September, 1950 (GoGoD 1950-98-22a)
The komi for the Honinbo Tournament was 4½ pts. at the time.
After
![black 31 :b31:](./images/smilies/b31.gif)
Elf estimates
Black's winrate as 93½% (27.7k playouts). Black won by 3½ pts.
- Click Here To Show Diagram Code
[go]$$Bcm29 Black is ahead.
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . O O X X . . . . . X a . O . X . . . |
$$ | . . . O . X . . X , . . . . . , X . . |
$$ | . . O . . . . . . . O . . . . . . . . |
$$ | . . . . . . . . . . . . . O . . . . . |
$$ | . . . . . . . . . . . . . . 3 X . . . |
$$ | . . . . . . . . . . . . . . . 2 . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O , . . . . . , . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . b . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . , X O . . . , . . . . . , . . . |
$$ | . . . X O O . . . O . . . . . O . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
Elf thinks that
![white 30 :w30:](./images/smilies/w30.gif)
is a mistake, losing 9% to the attachment at
a. For
![white 32 :w32:](./images/smilies/w32.gif)
Elf recommends the attachment at
b, but the play from there is complicated, and Elf regards
a, which Iwamoto played in the game, as only ½% worse, so I shall show Elf's continuation from there.
- Click Here To Show Diagram Code
[go]$$Bcm33 Elf's continuation from
, marked
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . 1 5 . . . . . . |
$$ | . O O X X . . . . . X W . O . X . . . |
$$ | . . . O . X . . X , . 2 . . . , X . . |
$$ | . . O . . . . 7 6 . O . . . . . . . . |
$$ | . . . 3 . . . . . . . . . O . . . . . |
$$ | . 4 . . . . . . . . . . . . X X . . . |
$$ | . . . . . . . . . . . . . . . O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O , . . . . . , . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . , X O . . . , . . . . . , . . . |
$$ | . . . X O O . . . O . . . . . O . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
![black 33 :b33:](./images/smilies/b33.gif)
is the underneath hane, to which White stands, solidifying his group.
![black 35 :b35:](./images/smilies/b35.gif)
takes kikashi in the top left and then
![black 37 :b37:](./images/smilies/b37.gif)
prevents White from making eye shape on the second line. The variation stops here, probably because the playouts for future play dropped below 1500.
Earlier in the game
- Click Here To Show Diagram Code
[go]$$Bc Unexpected error
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . 3 . . . . . . . . . 6 . . . . . |
$$ | . . . , . . . . . , . . . . . , 1 . . |
$$ | . . 4 . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . 5 . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . a . . . . . . . . . . . . 2 . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
![white 6 :w6:](./images/smilies/w6.gif)
is an error that loses 11½% to par, according to Elf. It is not that the ogeima approach is so bad, per se, it is that the 3-3 invasion at
a in the bottom left corner is so good. The value of these early 3-3 invasions was not suspected before the advent of AI.
Elf's mainline variation for
- Click Here To Show Diagram Code
[go]$$Wcm6 3-3 invasion
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , X . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . 0 . . . . . . . . . . . . . . . |
$$ | . . 9 8 . . . . . . . . . . . . . . . |
$$ | . . 7 6 . . . . . . . . . . . . . . . |
$$ | . . 5 X . . . . . . . . . . . . . . . |
$$ | . . . 3 4 . . . . , . . . . . , . . . |
$$ | . . 1 . 2 . . . . . . . . . . O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
White invades the bottom left corner and claims territory while Black makes a sizable wall.
- Click Here To Show Diagram Code
[go]$$Wcm16 3-3 invasion, continued
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . 4 , . 6 . . . , . . . 2 . , X . . |
$$ | . . O 5 . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . 7 . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . O X . . . . . . . . . . . . . . . |
$$ | . . O X . . . . . . . . . . . . 1 . . |
$$ | . . O X . . . . . . . . . . . . . . . |
$$ | . . . O X . . . . , . . . . . , . . . |
$$ | . . O . X . . . . . 3 . . . . O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
![white 16 :w16:](./images/smilies/w16.gif)
encloses the bottom right corner. Then
![black 17 :b17:](./images/smilies/b17.gif)
makes a two space high enclosure in the top right, which was not popular before the AI era.
![white 18 :w18:](./images/smilies/w18.gif)
extends on the bottom side, reducing Black's influence there. The bots have devalued the sides, but each corner has at least two stones in it. Next, Black plays a kick joseki in the top left corner, another joseki that was not popular before the bot era. Then,
![white 22 :w22:](./images/smilies/w22.gif)
jumps on the third line on the left side, making some territory and forming a 5 space extension from the two White stones in the corner. Dogma at the time was that such extensions are too far. The bots don't care.
Later in the game
- Click Here To Show Diagram Code
[go]$$Bcm19
blunders
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . 1 . . . . . . . . . . . . . . . . |
$$ | . 0 O X 3 . . . . . X . . O . X . . . |
$$ | . . . 2 . X . . X , . . . . . , X . . |
$$ | . . O . . . . . . . O . . . . . . . . |
$$ | . . . . . . . . . . . . . O . . . . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . 9 . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . , 5 8 . . . , . . . . . , . . . |
$$ | . . . X 4 6 . . . O . . . . . O . . . |
$$ | . . . 7 . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
Elf says that the natural looking extension,
![black 21 :b21:](./images/smilies/b21.gif)
, loses 19½% to par.
![white 22 :w22:](./images/smilies/w22.gif)
switches to the third line attachment against the Black enclosure in the bottom left corner.
![black 27 :b27:](./images/smilies/b27.gif)
secures territory in the bottom left co[rner. Then
![white 28 :w28:](./images/smilies/w28.gif)
descends in the top leftcorner. Instead of
![white 26 :w26:](./images/smilies/w26.gif)
Elf prefers
27 by 5½%.
Elf's recommended variation for
- Click Here To Show Diagram Code
[go]$$Bcm21 Atari first
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . 1 O X 7 . . . . . X . . O . X . . . |
$$ | . . 6 O . X . . X , . . . . . , X . . |
$$ | . . O . . . . . . . O . . . . . . . . |
$$ | . . . . . . . . . . . . . O . . . . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . 8 . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . , 3 . . . . , . . . . . , . . . |
$$ | . . . X 2 4 . . . O . . . . . O . . . |
$$ | . . . 5 . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
![white 26 :w26:](./images/smilies/w26.gif)
connects and
![black 27 :b27:](./images/smilies/b27.gif)
extends. White could have played this exchange earlier. Comparing the two diagrams, it seems like the main point playing the atari at
![black 21 :b21:](./images/smilies/b21.gif)
is this exchange.
Ironically, Elf regards the descent at
![white 28 :w28:](./images/smilies/w28.gif)
as a blunder, losing 20%.
![Wink ;)](./images/smilies/icon_e_wink.gif)
White has a superior play in the next diagram.
- Click Here To Show Diagram Code
[go]$$Wcm28 Third line attachment
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . O X X . . . . . X . . O . X . . . |
$$ | . . . O . X . . X , . . . . . , X . . |
$$ | . . O . . . . . . . O . . . . . . . . |
$$ | . . . . . . . . . . . . . O . . . . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O , . . . . . , . . . . . , . . . |
$$ | . 9 . 0 . . . . . . . . . . . . . . . |
$$ | . . 1 2 . . . . . . . . . . . . . . . |
$$ | . 3 X a . . . . . . . . . . . . . . . |
$$ | . 7 4 . . . . . . . . . . . . . O . . |
$$ | . 8 . X . . . . . . . . . . . . . . . |
$$ | . . 5 6 X O . . . , . . . . . , . . . |
$$ | . . . X O O . . . O . . . . . O . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
![white 38 :w38:](./images/smilies/w38.gif)
=
a![white 28 :w28:](./images/smilies/w28.gif)
plays a second third line attachment.
![black 29 :b29:](./images/smilies/b29.gif)
plays the top hane. (If
![black 29 :b29:](./images/smilies/b29.gif)
is at
a,
![white 30 :w30:](./images/smilies/w30.gif)
is the same.) After
![black 31 :b31:](./images/smilies/b31.gif)
pulls back. The peep,
![white 32 :w32:](./images/smilies/w32.gif)
, the crawl,
![white 34 :w34:](./images/smilies/w34.gif)
, and the cut,
![white 38 :w38:](./images/smilies/w38.gif)
, leave White some aji in the corner.
So Black and White traded blunders. Other than that,
![white 6 :w6:](./images/smilies/w6.gif)
missed the 3-3 invasion, which was probably heresy at the time. Other than that, Black took a strong lead because of an accumulation of relatively small errors by White.
Edited typos.