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Confused about scoring
http://lifein19x19.com/viewtopic.php?f=11&t=12263		 Page 1 of 1
Author:  cel70 [ Sat Sep 12, 2015 12:50 am ]
Post subject:  Confused about scoring
I've been trying go for a few months and greatly enjoying it. I've played western chess for about 20 years now and have a respectable Elo rating, and have in the past year branched out into Xian Qi (Chinese chess) and Shogi. I've read most of Go for Beginners by Kaoru Iwamoto. I understand the basic concepts such as eyes, ko threats, shicho etc.

But I have a big problem with determining territory scoring (and from browsing the internet it seems this aspect confuses other beginners too)

I upload a couple of pics of my last game, I played Black

Image

Image




So I was soundly thrashed! But why? as far as I can see all 3 of my black groups have 2 eyes at least. Shouldn't they be alive? Why has white "completely surrounded" anything?

The example of scoring given in the book was this
Image






which I totally understand. But I don't understand what happens when I always lose when playing go on my computer.



Appreciate any feedback. I'm keen to learn go, but not understanding scoring is as frustrating asknowing how the pieces move in chess but not knowing how to give checkmate! :lol:
Author:  Uberdude [ Sat Sep 12, 2015 12:58 am ]
Post subject:  Re: Confused about scoring
cel70 wrote:
But why? as far as I can see all 3 of my black groups have 2 eyes at least.


Can you mark where you think your two eyes are? My guess is you are confusing eyes with liberties. An eye is a space surrounded by only stones of your colour (or edge of board).
Author:  cel70 [ Sat Sep 12, 2015 1:32 am ]
Post subject:  Re: Confused about scoring
Uberdude wrote:
cel70 wrote:
But why? as far as I can see all 3 of my black groups have 2 eyes at least.


Can you mark where you think your two eyes are? My guess is you are confusing eyes with liberties. An eye is a space surrounded by only stones of your colour (or edge of board).



Aren't the 1- 5 and 1-7 points eyes? They're surrounded by my stones and the edge of the board.
Author:  Uberdude [ Sat Sep 12, 2015 1:53 am ]
Post subject:  Re: Confused about scoring
1-5 is indeed an eye but 1-7 is a false eye because 2-8 is a white stone. This means if white plays 1-9 you would need to fill in at 1-7 to protect your 1-8 stone but then 1-7 is not an empty space.
Author:  cel70 [ Sat Sep 12, 2015 2:06 am ]
Post subject:  Re: Confused about scoring
Uberdude wrote:
1-5 is indeed an eye but 1-7 is a false eye because 2-8 is a white stone. This means if white plays 1-9 you would need to fill in at 1-7 to protect your 1-8 stone but then 1-7 is not an empty space.



Ah, I see now! False eyes have been tripping me up. I briefly read about them in the book, but I assumed they were of little significance :oops:
Author:  HermanHiddema [ Sat Sep 12, 2015 2:07 am ]
Post subject:  Re: Confused about scoring
Ok, forget about eyes for a bit. Lets go with a simpler rule: Stones are dead if they cannot avoid being captured.

So now, for each of your groups, try to find a way to capture them. To make it easy, don't play any black moves. Just white moves. Can you find a sequence of white moves for each group that captures it?

Answers:
Click any of the marked moves (1, 2 or 3) to start, then keep clicking forward to see how stones get captured.



Ok, so suppose that black didn't pass every move, but also played. Is there a way he can prevent his stones from being captured?

Answer
No.

Try it out, and if you do think you can find a sequence, feel free to ask us!


The thing about eyes is not really the basic idea behind the life and death of groups. Eyes are a tool, a convenient way of thinking about positions, that help you recognize the vital points to prevent your groups from being captured.
Author:  cel70 [ Sat Sep 12, 2015 2:32 am ]
Post subject:  Re: Confused about scoring
Yes, that's much clearer now. From now on I'll be much more cautious about passing and knowing when to end the game!
Author:  cel70 [ Sat Sep 12, 2015 3:24 am ]
Post subject:  Re: Confused about scoring
Okay just one more example would really clarify, then I'll study the book more!

I just played this a few minutes ago.


Image

Image


In this one I see my top group of 4 black stones is lost. White can play either 1-5 or 4-4 and there's no saving my stones no matter what.


The other two groups, I'm not certain. My group on the right has no internal eyes, does that mean it's lost? Hasn't my group in the lower left also captured territory? To be honest it would help a lot if I knew what the symbols on the computer screen meant, but "Aya" was a freeware program that came with no useful documentation
Author:  EdLee [ Sat Sep 12, 2015 3:57 am ]
Post subject: 
Quote:
My group on the right has no internal eyes, does that mean it's lost?
Hi cel,

Please study Herman's post 6. (Again, and again. :) )
Follow his suggestions/procedures for your right group.

If you still get stuck, then ask for more hints. :)

Yes, your lower left group has some territory.
Author:  cel70 [ Sat Sep 12, 2015 10:03 am ]
Post subject:  Re: Confused about scoring
Yes, Hermans post was very helpful and has clarified points.

But the symbols the "Aya" program use post game are confusing me. I haven't seen them used in any go books yet. Presumably the "X" refer to stones that can't be saved in any way.Bbut what does it mean when a stone of mine has a small white dot in the middle, is that saying it's captured those stones? And what are the blue and white crosses? Sorry but as I said Aya came with little useful documentation! :-? Understanding what it's trying to tell would go a long way in helping me play better.
Author:  Jujube [ Sat Sep 12, 2015 1:45 pm ]
Post subject:  Re: Confused about scoring
I don't know how Aya works or what the meaning of all those symbols are, but it looks a bit crazy. Like something exploded in Aya's program.

Your bottom-left group is alive. Remember the saying: "two eyes is alive". The group has a one-point eye at 2-6 and another 6-point eye from 1-8 to 2-9. This group gives you 7 points of territory. The White stone at 2-9 is dead, which gives you an extra point. The rest of the board is White's.

One part of Go is training the brain to recognise patterns. With your chess ability, you know whether moving the Knight will fork those two pieces, and you know it almost instinctively, like the idea pops into your head. Or, at the end of the game, with King & 1 Pawn vs King, you know instinctively whether the position looks drawn or looks winning. Same as Go, once you play more games, you will instinctively know whether simple groups of yours and your opponent's look alive or dead.

I just wanted to mention also that if a group of yours is unconditionally alive (which means that it's alive even if White plays first), you don't need to make two eyes in it - otherwise you are filling in your own territory. Just leave it. Of course, if White decides that it is able to be killed and tries to kill it, you probably need to respond in that case :)
Author:  emeraldemon [ Sat Sep 12, 2015 3:33 pm ]
Post subject:  Re: Confused about scoring
This might help:
http://senseis.xmp.net/?IntroductionToLifeAndDeath

If you haven't seen it yet, Sensei's Library is a wiki devoted to go, with lots of good (and some bad) information on it.

Playing with humans will also help, since they can explain more.

Some ways to play online:
https://online-go.com/ - in browser, some realtime and some correspondence games
http://www.tygemgo.com/ - largest go server I think, based in Korea
http://www.gokgs.com/ - java client, maybe more western players
http://www.dragongoserver.net/ - the correspondence game server I use

We also play "malkovich" games on this server, where people put thoughts in hidden comments for people to see:
viewforum.php?f=37
I will play you if you want :)
Author:  xed_over [ Sat Sep 12, 2015 11:18 pm ]
Post subject:  Re: Confused about scoring
cel70 wrote:
But the symbols the "Aya" program use post game are confusing me. I haven't seen them used in any go books yet. Presumably the "X" refer to stones that can't be saved in any way.Bbut what does it mean when a stone of mine has a small white dot in the middle, is that saying it's captured those stones? And what are the blue and white crosses? Sorry but as I said Aya came with little useful documentation! :-? Understanding what it's trying to tell would go a long way in helping me play better.

Aya is a little confused.
Most Go problems can't determine live and dead stone status on their own, and need the human opponent to mark which stones are dead.

The squares on the otherwise empty spots are trying to indicate which color owns that territory. The same with the circles on the actual stones. But there are some spots that its confused about (the blue and red crosses), and it can't decide exactly how it should be scored and if the stones are live or dead. The stones with the X's are definitely being marked dead.

If it doesn't offer you an option to mark dead stones before scoring, then maybe it'll let you resume playing to go ahead and either capture (or attempt to live until captured).

Most computer programs use Chinese rules for this very reason (that they can't figure out what it alive or dead) -- so just keep playing until only live stone remain on the board.
Author:  cel70 [ Sun Sep 13, 2015 1:57 am ]
Post subject:  Re: Confused about scoring
Thanks guys. What a relief! If I'd stuck with Aya I think I'd be banging my head on the keyboard in frustration. So I'll invest in a better program, or even play online.

Anyway, all these posts have been very helpful, and I'll probably spend the rest of the day studying my book :study: The section on false eyes too really helped me differentiate between false and true eyes.
Author:  leichtloeslich [ Sun Sep 13, 2015 6:12 am ]
Post subject:  Re: Confused about scoring
Quote:
I'll invest in a better program, or even play online.

there are better alternatives that are free. Check out pachi, fuego and gnu go. The first two engines are fairly strong on smaller boards and it will likely be years before you can beat them evenly, if at all.
I recommend pachi, it even has precompiled windows binaries, though I haven't tried those.
All of these engines come without a graphical user interface btw and you'll want to plug them into a gtp host like gogui.

Oh and for learning the basic rules I definitely recommend asking on KGS or OGS for teaching games on 9x9. Have fun.
Author:  Bill Spight [ Sun Sep 13, 2015 7:10 am ]
Post subject:  Re: Confused about scoring
Hi, cel70. Welcome to go! :)

You have gotten some good advice. Let me just add a comment or two. :)

You are having trouble telling which stones are alive or dead. That is normal for a beginner. And let me assure you that even players much stronger than you sometimes have that kind of problem, too. Usually because they think that some stones are alive that can be killed or captured.

The good news is that it won't take too long before you will be able to tell which stones are alive or dead at the end of the game with great accuracy. For now, you should just play on until the status of every stone seems clear to you. And make sure that all the dame are filled, except in seki, OC.

Doing so may cost you some points by Japanese (territory) scoring, but learning to tell which stones are dead is more important. If that bothers you, you can play by Chinese (area) scoring.

Let me illustrate with your last diagram. I suppose that it is Black's turn, either because White just passed, or because Black has captured one White stone. There are still dame on the board.
Author:  xed_over [ Sun Sep 13, 2015 8:33 am ]
Post subject:  Re: Confused about scoring
cel70 wrote:
If I'd stuck with Aya I think I'd be banging my head on the keyboard in frustration. So I'll invest in a better program, or even play online.

There's nothing wrong with Aya.

As Bill illustrates, the game status was still in an ambiguous state (which is why Aya was confused and didn't know how to score the game properly). Depending on your continued play, the game could still go either way.

I would suspect that the programs that leichtloeslich recommended would have the same, or at least similar problems with the same position. Not to mention that you probably can't install those as easily on your phone -- making "better" relative.
Author:  Schachus [ Sun Sep 13, 2015 10:23 am ]
Post subject:  Re: Confused about scoring
Sorry, I didnt look carefully...

But still, :b7: at 1-2 would be another reason, why :w4: in the lecond variation is bad
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