In a recent game over on the Dragon Go Server in which I had black, we reached the following position:

Click Here To Show Diagram Code

[go]$$W
$$ --------------------------------------
$$ |. O X X X . . X O O . O X X X X . X .|
$$ |. O O O X X . . X O . O O O X X X O O|
$$ |. . . . O X . . X O . . . O . X O O .|
$$ |. . . O O X . . X X O O . . X X O X X|
$$ |. . . O X X . X . X X X O O . X O X .|
$$ |. . O . O . X O . X O O . O . X O O X|
$$ |. . . O X X X O O X X O O X X X O O .|
$$ |. . O X . . . X O X O O X . . . X O O|
$$ |. . O X X X X X O O O X X . . . X X O|
$$ |. O O O X O X O . O O O . X . , . X O|
$$ |X X X X O O O O . . X . O X . . . O X|
$$ |. . . X O . . . . O X O . O X . . O X|
$$ |. X . X X O O . O . O O O X . . . . X|
$$ |. . X O O X X . . . . . . X . . . . .|
$$ |. X X X O O X X X X X X X X . . . . .|
$$ |X O O O O O . . . O X O X O X X X X X|
$$ |. O . O X . O X . O O O O O X O O O X|
$$ |O X X O . X O X . O . O . O O . . . O|
$$ |. X O O . X X . X . . O . . . . . O .|
$$ --------------------------------------
$$ White has captured two stones; Black has captured one[/go]

I logged in to DGS to play my next move, Black 233, and was surprised to see that for White 232, White... resigned, saying "Thanks, I counted."

I had been counting too, and was convinced I was behind. There are two big sekis in the top right and bottom left, but beyond that, White has:

2 prisoners already
12 points in the lower right
16 points in the center plus two prisoners
21 points on the left
6.5 points komi

For a total of 59.5 give or take depending on how we both handle the endgame.

Black has:

1 prisoner already
7 points on the left
12 points on the top
30 points on the right plus two prisoners

Any way I count it, Black is behind by several points.

So I fired up Cgoban, and the results were shocking. It said White was ahead by 18.5, except that this included all the stones in the bottom left which it claimed were dead; take that territory away from White and Black should theoretically be leading. I played out the seki on the bottom left and the score changed wildly.

So what's going on with this game (other than the fact that it's over now)?

I seem to be having difficulty getting the diagram to show properly and can't open the "How to make a diagram" thread, so if it doesn't show up, here's the SGF:



I'm not particularly looking for a review here, since I haven't gone over the rest of the game. I do have a feeling we both screwed up the corners that wound up sekis, however.

The bottom left is not a seki , but that doesn't change the fact that you'e right that white is ahead… but I could very well be missing something too…

_________________
Patience, grasshopper.

White probably thought the top right was dead.

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Still officially AGA 5d but I play so irregularly these days that I am probably only 3d or 4d over the board (but hopefully still 5d in terms of knowledge, theory and the ability to contribute).

Daal: How does White kill Black in the bottom left?

DrStraw: When I played 175 at S15, I thought I was actually going to kill the White group. (I thought I was going to kill the White group in the bottom left, too.... )

The lower left was seki until you played an extra move to create a bend 4 shape inside.

_________________
Still officially AGA 5d but I play so irregularly these days that I am probably only 3d or 4d over the board (but hopefully still 5d in terms of knowledge, theory and the ability to contribute).

Apologies. I was looking on my phone at a variation.

_________________
Patience, grasshopper.

But if White tries to kill those stones, White will end up with just 3 spaces inside, and Black can kill that, right?

Obviously, Black can't kill White. If Black plays A1 then B2 and C2 become miai; if Black plays C3 then B1 and B2 become miai.

Now that you know these seki shapes, take another look at both corners. If you are safely ahead, seki may be the best option, but sometimes there are possibilities for ko.

Other possibilities for B101?
Other possibilities for B181?