The game is GoGoD 2010-08-19i between Iyama Yuta (W) and O Meien.
Iyama chose to save the two White stones.
- Click Here To Show Diagram Code
[go]$$Wcm24 Save Our Stones
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . 2 . . . . . . . . . . . . . . . . |
$$ | . 1 X O O . . . . . . . . . . . . . . |
$$ | . W W X 4 5 . . . . . . . . . . . . . |
$$ | . B B 3 6 . . . . , . . . . . , . . . |
$$ | . . . 7 . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . X O . . . . . . . . . . . . . . . |
$$ | . . X , . O O O . , . . . . . , . . . |
$$ | . . . X . X X . . . . . . . X . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
added a dame to the
stones in sente. After
O Meien had the choice of sacrificing the
stones or losing 3 stones in a ladder.
- Click Here To Show Diagram Code
[go]$$Bcm31 Game continuation
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . 7 . . . . . . . . . . . . . . . . |
$$ | . 9 8 O . . . . . , . . . . . X . . . |
$$ | . c . . 6 . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . X . 4 b 0 . . . . . . . . . . . . |
$$ | . O X O O 3 . . . . . . . . . . . . . |
$$ | . O O X X O 5 . . . . . . . . . . . . |
$$ | . X X O X 1 . . . , . . . . . , . . . |
$$ | . a 2 O . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . X O . . . . . . . . . . . . . . . |
$$ | . . X , . O O O . , . . . . . , . . . |
$$ | . . . X . X X . . . . . . . X . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
O Meien saved his three stones, and even got in a ponnuki. For
Elf prefers
a, but only by 0.1%. For
Elf prefers
b by ½%, a difference that may be attributed to noise. For
, however, Elf prefers
c by 4½%, which is too large for noise, even if it is within Elf's margin of error.
- Click Here To Show Diagram Code
[go]$$Wcm40 Variation for
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . 2 . . . . . . . . . . . . . . . . . |
$$ | . . X . 4 . . . . . . . . . . . . . . |
$$ | . X O O . . . . . , . . . . . X . . . |
$$ | . 1 3 . O . . . . . . . . . . . . . . |
$$ | . . X . 7 6 . . . . . . . . . . . . . |
$$ | . . X . O . . . . . . . . . . . . . . |
$$ | . O X O O X . . . . . . . . . . . . . |
$$ | . O O X X . X . . . . . . . . . . . . |
$$ | . X X O X X . . . , . . . . . , . . . |
$$ | . . O O . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . X O . . . . . . . . . . . . . . . |
$$ | . . X , . O O O . , . . . . . , . . . |
$$ | . . . X . X X . . . . . . . X . 5 . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
White makes territory on the left side in exchange for the top left corner and Black strength in the center, but White also gets the 3-3 invasion in the bottom right corner.
Now let's go back and see Elf's mainline variation for
.
- Click Here To Show Diagram Code
[go]$$Wcm36 Mainline variation for
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . 0 . . . . . . . . . . . . . . . . . |
$$ | . 6 5 7 . . . . . . . . . . . . . . . |
$$ | . . 4 O . . . . . , . . . . . X . . . |
$$ | . . . 2 3 . . . . . . . . . . . . . . |
$$ | . . B . . . . . . . . . . . . . . . . |
$$ | . 8 B . O 1 . . . . . . . . . . . . . |
$$ | . O B O O X . . . . . . . . . . . . . |
$$ | . O O X X . X . . . . . . . . . . . . |
$$ | . X X O X X . . . , . . . . . , . . . |
$$ | . 9 O O . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . X O . . . . . . . . . . . . . . . |
$$ | . . X , . O O O . , . . . . . , . . . |
$$ | . . . X . X X . . . . . . . X . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
With
this line transposes to Elf's mainline variation for
.
This way White lets Black save his
stones and extend into the corner.
- Click Here To Show Diagram Code
[go]$$Wcm46 Mainline variation for , continued
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . X . . . . . . . . . . . . . . . . . |
$$ | . X O O . . . . . . . . . 5 . . . . . |
$$ | . . X O . . . . . , . . . . . X . . . |
$$ | . . . X O . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . X X . O O . . . . . . . . . . . . . |
$$ | . O X O O X . 1 . 3 . . . . . . . . . |
$$ | . O O X X . X . . . . . . . . . . . . |
$$ | . X X O X X . . 2 , 4 . . . . , . . . |
$$ | . O O O . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . X O . . . . . . . . . . . . . . . |
$$ | . . X , . O O O . , . . . . . , . . . |
$$ | . . . X . X X . . . . . . . X . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
and
attack Black's central stones, pushing them further into the center. Along with
they build a large White sphere of influence on the top side.
Top choice: Give up the stones
- Click Here To Show Diagram Code
[go]$$Wcm24 Sacrifice
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . B 7 . . . . . . . . . . . . . . . |
$$ | . 5 3 . . . . . . . . . . . . . . . . |
$$ | . 4 X O O . . . . . . . . . . . . . . |
$$ | 6 W W X 1 . . . . . . . . . . . . . . |
$$ | . X X 2 . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . X O . . . . . . . . . . . . . . . |
$$ | . . X , . O O O . , . . . . . , . . . |
$$ | . . . X . X X . . . . . . . X . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
completes a standard pattern for sacrificing the
stones. The
stone still has a bit of aji left.
- Click Here To Show Diagram Code
[go]$$Bcm31 Mainline, continued
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . 5 . 4 . 3 . . . 2 . . . . . |
$$ | . . . O . . . . . , . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X O . . . . . . . . . . . . . . . |
$$ | . O O . . . . . . . . . . . . . . . . |
$$ | . X X O O . . . . . . . . . . . . . . |
$$ | X . . X O . . . . . . . . . . . . . . |
$$ | . X X X . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . X O . . . . . . . . . . . . . . . |
$$ | . . X , . O O O . , . . . . . , 1 . . |
$$ | . . . X . X X . . . . . . . X . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
encloses the bottom right corner. Then
approaches the top right corner.
-
make an amusing flow of the stones.
This is a question of judgement. My own feeling, going back to when I was an SDK, is that the sacrifice is a clear way to cash in on the White thickness in the lower left, while capturing the 2 Black stones leaves White overconcentrated on the left side. So I am not surprised that Elf prefers the sacrifice. I am surprised, even knowing of Elf's extreme views, that it prefers it by a whopping 47%!
I expect that other top bots will also prefer the sacrifice. It would be interesting to see by how much.