Life In 19x19
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Scoring question
http://lifein19x19.com/viewtopic.php?f=11&t=14573		 Page 1 of 1
Author:  mvk20 [ Sat Sep 30, 2017 3:05 pm ]
Post subject:  Scoring question
I had a game on IGS that I am really not sure how it should have ended. I had a group in the corner that my opponent thought was dead, but I thought was alive in seki. I passed first. We scored it, and if the group was dead he won, and if it was seki I won. We couldn’t figure out how to start the game again to play it out. We chatted about it, and we agreed that if I had played B3 it was seki, if he had played B3 it was dead. We both tried to resign and give the victory to the other player, he hit the button first. I even offered to start a new game with him and resign so he would get a win too.

How does this work? Can you resume the game somehow on IGS? On a resume, who plays first? Me, because he’s the attacker and he has to prove I’m dead?

Thanks for any help and advice!
Author:  BlindGroup [ Sat Sep 30, 2017 3:21 pm ]
Post subject:  Re: Scoring question
On IGS, you can't play it out. In the toolbox menu there is an option to have someone else score it. If you do that, an administrator will score the game in a day or so.
Author:  mvk20 [ Sat Sep 30, 2017 3:33 pm ]
Post subject:  Re: Scoring question
Thanks, that answers one of my questions. How would the admin have scored it? I could have saved it with a move, he could have killed it with a move.
Author:  djhbrown [ Sat Sep 30, 2017 3:48 pm ]
Post subject:  Re: Scoring question
Automatic scorers sometimes get it wrong, especially when seki is involved. You can download the .sgf of your file from IGS and upload it here as a post attachment and i'm sure someone will tell you which of you was correct.

if a doubtful situation arises again, you can always not pass until you have filled in all the dame, and then the automatic scorer should get it right.
Author:  mvk20 [ Sat Sep 30, 2017 4:07 pm ]
Post subject:  Re: Scoring question
Here's the sgf...

I'm still more curious about the concept than this one actual game though. If the game ends in an unsettled situation such as this, how does it get scored? Like for example, what if both players pass when there is a group with a 3 point eye space on the board? Is it dead because it could have gotten killed with one more play? Or is it alive because it could have been saved with one more play? That is basically the type of situation I'm talking about.

Attachments:
goofy11-mvk20(B) IGS.sgf [1.29 KiB]
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Author:  Bill Spight [ Sat Sep 30, 2017 4:21 pm ]
Post subject:  Re: Scoring question
mvk20 wrote:
Thanks, that answers one of my questions. How would the admin have scored it? I could have saved it with a move, he could have killed it with a move.


The Black group is dead. I have spoken. :ugeek: Here is the SGF file that shows why. Go to the end.



Oh, here is a hint. Fill all the dame before ending play. It will help clarify matters. And it may open up opportunities. :mrgreen:
Author:  Bill Spight [ Sat Sep 30, 2017 4:27 pm ]
Post subject:  Re: Scoring question
mvk20 wrote:
Here's the sgf...

I'm still more curious about the concept than this one actual game though. If the game ends in an unsettled situation such as this, how does it get scored? Like for example, what if both players pass when there is a group with a 3 point eye space on the board? Is it dead because it could have gotten killed with one more play? Or is it alive because it could have been saved with one more play? That is basically the type of situation I'm talking about.


What happens depends upon the rules, and each rule set handles that kind of situation differently. The professional Japanese rules allow play to resume, with the opponent of the player who makes the request playing first. If neither player requests a resumption, both lose. That's pretty harsh, IMO. For amateurs I think that a void game is better. :)
Author:  mvk20 [ Sat Sep 30, 2017 4:34 pm ]
Post subject:  Re: Scoring question
Black to play dies even if he plays B3?
Author:  mvk20 [ Sat Sep 30, 2017 4:40 pm ]
Post subject:  Re: Scoring question
I also just don’t understand the general principle on the scoring disputes, of who would play first on a restart in the event that a group truly is unsettled, like the 3 point eye space? Is the onus on the killer to kill it, or on the groups owner to have 2 distinct eyes? If I say a group is alive, and my opponent says it’s dead, who is requesting the restart?

It’s really not this particular game that I’m worried about so much as it is the general rule so I know for future situations.
Author:  Bill Spight [ Sat Sep 30, 2017 6:02 pm ]
Post subject:  Re: Scoring question
mvk20 wrote:
Black to play dies even if he plays B3?


Sure. I have added a variation for that. :)
Author:  Bill Spight [ Sat Sep 30, 2017 6:09 pm ]
Post subject:  Re: Scoring question
mvk20 wrote:
I also just don’t understand the general principle on the scoring disputes, of who would play first on a restart in the event that a group truly is unsettled, like the 3 point eye space?


Well, IGS rules are not, I believe, Japanese pro rules, so you would have to find out how IGS handles that kind of situation.

As for the 3 pt. eye space under the Japanese professional rules -- not that a Japanese pro would face such a thing -- if the player with the eye requests resumption, the other player plays on the center point of the eye and kills the group, and if the other player requests resumption, the player with the eye plays on the center point and lives. If the life or death of the group affects who wins the game, neither player will be inclined to resume the game, and both may lose. Not for amateurs, as I said.
Author:  mvk20 [ Sat Sep 30, 2017 6:23 pm ]
Post subject:  Re: Scoring question
Thanks for adding that line to the sgf - I should have been able to see that, but then again, if you look at the whole game there’s lots of stuff I should be seeing :)

As for the pro rules, understanding that they are just pro rules, if both players pass and they can’t agree on the score, they both lose, unless one requests a resumption. If one requests a resumption, the other begins play. Did I get that right?

Thanks again - I really appreciate your help!
Author:  Bill Spight [ Sat Sep 30, 2017 6:34 pm ]
Post subject:  Re: Scoring question
mvk20 wrote:
Thanks for adding that line to the sgf - I should have been able to see that, but then again, if you look at the whole game there’s lots of stuff I should be seeing :)


Fill the dame before passing. That helps. :)

Quote:
As for the pro rules, understanding that they are just pro rules, if both players pass and they can’t agree on the score, they both lose, unless one requests a resumption. If one requests a resumption, the other begins play. Did I get that right?


Close. After passing and before agreement, if one player requests resumption of play, play resumes with the other player playing first. The both lose rule applies only if there is an unsettled group and neither player requests resumption. Otherwise, there is a procedure to determine life and death by hypothetical play.

Quote:
Thanks again - I really appreciate your help!


De nada. :)
Author:  djhbrown [ Sat Sep 30, 2017 7:25 pm ]
Post subject:  Re: Scoring question
Swim agrees with Bill's conclusion, from this logical reasoning:

in the top left, black has a single cluster, which is obviously dead because (a) it is fully surrounded by white's colour map, and white is obviously alive, and (b) it has only one internal colour-controlled point (B19) which isn't enough to make 2 eyes

in the bottom left, the best black could hope for is to capture a shape which is one of the killing shapes because it has a single central point on which white can play to reduce it to a single eye. https://senseis.xmp.net/?KillingShapes

note: "obviously alive and "obviously dead" are defined by Swim in https://ssrn.com/abstract=3027817 (gomap doesn't (yet?) perform obvious life and death analysis but you can easily see it for yourself)

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