The game is GoGoD 2003-01-20o, between Otake Hideo, 9 dan (W), and Oya Koichi, 9 dan.
- Click Here To Show Diagram Code
[go]$$Bcm37 Drive towards thickness? Mistake.
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . O . . . . . . . . . . . . . |
$$ | . . O , . . . . . , . . . . . X . . . |
$$ | . . O X . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . 1 . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . 4 , O . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . O . . . . . . . . . . . . . e a . . |
$$ | . . . X X . . . . . . . . . . . 2 . . |
$$ | . . O O . . . . . . . . . . . . . 3 . |
$$ | . . . . . X . . . . . . . . . . c b . |
$$ | . . . O . . . O X X X X . . . X . d . |
$$ | . . O . . X . O O . O O X X . . . . . |
$$ | . . . X . . O . . . . O O X . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
Elf reckons that
![black 37 :b37:](./images/smilies/b37.gif)
loses 12½% to the approach at
a, making it a definite mistake.
9 dans do not blindly follow proverbs, OC, but surely the one about driving the opponent's stones towards thickness was in the back of Oya's mind. And he was surely aware of the threat of
![white 38 :w38:](./images/smilies/w38.gif)
to slide to
b or otherwise take advantage of the weakness of Blacks' corner by playing at
c or
d, for instance. It is likely that he planned to reply to
![white 38 :w38:](./images/smilies/w38.gif)
with
![black 39 :b39:](./images/smilies/b39.gif)
before he decided on
![black 37 :b37:](./images/smilies/b37.gif)
. Unfortunately, Elf regards
![black 39 :b39:](./images/smilies/b39.gif)
as losing 9% by comparison with the kosumi at
c, which threatens the shoulder hit at
e.
Otake's play does not escape criticism, either.
![white 38 :w38:](./images/smilies/w38.gif)
, a two space extension that makes a base, and
![white 40 :w40:](./images/smilies/w40.gif)
, a one space jump, are bread and butter plays, but they are minor errors, or at least questionable. Elf reckons that
![white 38 :w38:](./images/smilies/w38.gif)
loses 5% to par and
![white 40 :w40:](./images/smilies/w40.gif)
loses 6%. IMO the bots are going to lead to a profound reconsideration of what we think we know about go, something that by human progress alone would have taken centuries to accomplish.
Let's take another look at
![white 40 :w40:](./images/smilies/w40.gif)
, through Elf's eyes.
- Click Here To Show Diagram Code
[go]$$Wcm40 Variation for ![white 40 :w40:](./images/smilies/w40.gif)
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . O . . . . . . . . . . . . . |
$$ | . . O , . . . . . , . . . . . X . . . |
$$ | . . O X . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . 6 . . . . . , . . . . . , O . . |
$$ | . . X 5 4 . . . . . . . . . . . . . . |
$$ | . O 3 7 8 . . . . . . . . . . . . . . |
$$ | . . . X X . . . . . . . . . . . O . . |
$$ | . . O O . . 1 . . . . . . . . . . X . |
$$ | . . . . . X . . . . . . . . . . . . . |
$$ | . . . O . . . O X X X X . . . X . . . |
$$ | . . O . . X . O O . O O X X . . . . . |
$$ | . . 2 X . . O . . . . O O X . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
![white 40 :w40:](./images/smilies/w40.gif)
switches to the bottom left, threatening to cut off three Black stones.
![black 41 :b41:](./images/smilies/b41.gif)
replies strongly by crawling into the White corner.
![white 42 :w42:](./images/smilies/w42.gif)
bolsters the White group with sente.
- Click Here To Show Diagram Code
[go]$$Wcm48 Variation for
, continued
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . O . . . . . . . . . . . . . |
$$ | . . O , . . . . . , . . . . . X . . . |
$$ | . . O X . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . , . . . . . , O . . |
$$ | . . X O X . . . . . . . . . . . . . . |
$$ | . O O O X . . . . . . . . . 3 5 . . . |
$$ | . . . X X . . . . . . . . . . 4 O 1 . |
$$ | . . O O . . O . . . . . . . . . 2 X . |
$$ | . . . . . X . . . . . . . . . . . . . |
$$ | . . . O . . . O X X X X . . . X . . . |
$$ | . . O . . X . O O . O O X X . . . . . |
$$ | . . X X . . O . . . . O O X . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
![white 48 :w48:](./images/smilies/w48.gif)
returns to the right side and blocks on the 2d line, making some territory. By comparison with
![white 40 :w40:](./images/smilies/w40.gif)
, White in this line of play on the right side makes territory and counters the influence of the Black wall.
Next, Elf's mainline variation for
![white 38 :w38:](./images/smilies/w38.gif)
is instructive.
- Click Here To Show Diagram Code
[go]$$Wcm38 Threaten the corner first
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . O . . . . . . . . . . . . . |
$$ | . . O , . . . . . , . . . . . X . . . |
$$ | . . O X . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , O 6 . |
$$ | . . X . . . . . . . . . . . . . 5 4 . |
$$ | . O . . . . . . . . . . . . . . . . . |
$$ | . . . X X . . . . . . . . . . . 3 . . |
$$ | . . O O . . 7 . . . . . . . . . . . . |
$$ | . . . . . X . . . . . . . . . . 1 . . |
$$ | . . . O . . . O X X X X . . . X 2 . . |
$$ | . . O . . X . O O . O O X X . . . . . |
$$ | . . 8 X . . O . . . . O O X . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
![white 38 :w38:](./images/smilies/w38.gif)
plays kikashi against the corner before making a base with
![white 40 :w40:](./images/smilies/w40.gif)
. (If Black plays at
40 instead of blocking the corner, White can push into the corner at
39.)
![black 41 :b41:](./images/smilies/b41.gif)
undercuts the White base, but
![white 42 :w42:](./images/smilies/w42.gif)
simply blocks on top.
![white 44 :w44:](./images/smilies/w44.gif)
switches to the bottom left.
Top choice: Approach from the bottom
- Click Here To Show Diagram Code
[go]$$Bcm37 Extend from the wall
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . O . . . . . . . . . . . . . |
$$ | . . O , . . . . . , . . . . . X . . . |
$$ | . . O X . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . . 5 . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . a W . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . O 4 . . . . . . . . . . . . . 1 . . |
$$ | . . . X X . . . . . . . . . . . . . . |
$$ | . . O O . 3 2 . . . . . . . . . . . . |
$$ | . . . . . X . . . . . . . . . . . . . |
$$ | . . . O . . . O X X X X . . . X . . . |
$$ | . . O . . X . O O . O O X X . . . . . |
$$ | . . . X . . O . . . . O O X . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
![black 37 :b37:](./images/smilies/b37.gif)
extends from the bottom corner. The fact that it might be close to the Black wall is no big deal. In fact, Black is building a territorial moyo.
![white 38 :w38:](./images/smilies/w38.gif)
switches to the bottom left, and plays into the center, as well. Takagawa points out that it is by no means necessary to make a base or extend from a side wedge like
![white with circle :wc:](./images/smilies/wc.gif)
, even though the ability to do so is part of the rationale for the play. Takagawa argues that preventing Black's ideal extension to
![white with circle :wc:](./images/smilies/wc.gif)
or
a is good enough. OTOH, the bots don't think much of those extensions early in the game.
![Wink ;)](./images/smilies/icon_e_wink.gif)
Anyway, in the mainline variation White tenukis and later
![black 41 :b41:](./images/smilies/b41.gif)
plays an enclosure cum 3 space pincer against
![white with circle :wc:](./images/smilies/wc.gif)
.
- Click Here To Show Diagram Code
[go]$$Wcm42 Mainline, continued
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . O . . . . . . . . . . . . . |
$$ | . . O , . . . . . , . . . . . X . . . |
$$ | . . O X . . . . . . . . . . . . . . . |
$$ | . . X . . 0 . . . . . . . . . . X . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . 9 . . . . . . . . . . . . . |
$$ | . . . . 7 . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , O . . |
$$ | . . X 1 . . . . . . . . . . . . . . . |
$$ | . O O . . . 4 8 . . . . . . 6 . X . . |
$$ | . . . X X . 2 3 . . . . . . . . . . . |
$$ | . . O O . X O 5 . . . . . . . . . . . |
$$ | . . . . . X . . . . . . . . . . . . . |
$$ | . . . O . . . O X X X X . . . X . . . |
$$ | . . O . . X . O O . O O X X . . . . . |
$$ | . . . X . . O . . . . O O X . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
The hane,
![white 42 :w42:](./images/smilies/w42.gif)
, is a strong play dividing Black in two on the left side and attacking both ways.
![black 43 :b43:](./images/smilies/b43.gif)
bolsters his stones in the bottom left with sente. Then
![black 47 :b47:](./images/smilies/b47.gif)
extends Black's territorial moyo into the center, as anticipated by Knotwilg, pwaldron, and, I suppose, John Fairbairn.
![Smile :)](./images/smilies/icon_e_smile.gif)
White now continues the attack on the left side.
I would have chosen the approach of
![black 37 :b37:](./images/smilies/b37.gif)
in this game until I ran across a Jowa game years ago where Black played an side extension from a wall that seemed to me to be too close and thus a bit inefficient, and then played a one space jump from it, making territory from thickness.
![Surprised :o](./images/smilies/icon_e_surprised.gif)
I decided that maybe Jowa was right and I wasn't.
![Wink ;)](./images/smilies/icon_e_wink.gif)
I think that the bots like the way top players in the 19th century handled play on the side over the way that top players in the 20th century did. This is another example, it seems to me.
![Smile :)](./images/smilies/icon_e_smile.gif)