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Disputed (?) score
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Author:  tekesta [ Fri Jul 05, 2013 9:10 am ]
Post subject:  Disputed (?) score
I just played this game on IGS. The score is W + 134.5 . I find it hard to believe since Black has almost the entire right side and the bottom left corner (thanks to a gross oversight on my part). I guess the scoring procedure was not carried out properly; sometimes on IGS I experience difficulties marking a stone as either live or dead.



According to my calculations (vacant pts. - prisoners = score), for Black, 76 - 13 = 63 pts. For White, 121 - 8 = 113 pts. So, 113 - 63 = 50 pts.

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Author:  amnal [ Fri Jul 05, 2013 9:16 am ]
Post subject:  Re: Disputed (?) score
It looks like this sgf includes markers showing which stones have been marked as dead, and which areas are being scored for each colour. Assuming these markers reflect what the server (and your client) thinks is true, the score is indeed wrong, as the dead white stones in black's upper right territory have not been marked as dead. The surrounding territory is thus not recognised as black's.

My own client (I use qgo) gives the score as W 123.5 (including komi) to B 84. White really wins by 39.5.
Author:  Joaz Banbeck [ Fri Jul 05, 2013 10:17 am ]
Post subject:  Re: Disputed (?) score
By my count, black was undercounted by 71. But even with a correct count, white still wins. :sad:

tekesta wrote:
...
According to my calculations (vacant pts. - prisoners = score)...


Sorry, but that is not correct.

vacant points + prisoners*2 = score

or another way of stating it is take all the prisoners off the board, then

vacant points + prisoners = score.

-------------------------------------------------

As an example of correct counting:

In the lower right, black has 11 points.

If you take the prisoners off, there are 9 points of territory and 2 prisoners. + 2 = 11

If you leave the prisoners on, there are 7 points of empty territory, and 2 prisoners which are counted at two points each ( 1 for the prisoner and 1 for the territory that it occupies ) for 4 points. 7 + 4 = 11.
Author:  tekesta [ Fri Jul 05, 2013 1:49 pm ]
Post subject:  Re: Disputed (?) score
I noticed this last player played very passively. I would've expected him/her to have groups all over the board, but almost all the Black activity was on the right side of the board. I almost killed the Black group in the lower left corner, but a gross oversight on my part allowed it to live. After that I had to quickly fortify the lower White group and restrict the expansion of the newly created Black group in the lower left corner.

As for the scoring formula, looks like I did not explain it well. "Vacant points surrounded by my side minus stones lost to the opponent equals the final score" was what I meant to say, but Banbeck's explanation is closer to the truth. It's just that I'm accustomed to thinking "vacant points minus lost stones" when doing Japanese scoring.
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