Territory Confusion

ThataintChessisit · Post by **ThataintChessisit** » Fri Nov 21, 2014 12:36 pm

Heyall,

my friend and I decided to learn Go, and we had some fun games, but we always stumbled across this one thing about territory that confused us:

Lets take this picture for example. As I would assume, the upper part belongs to the black player and the down part to the white player. But why cant the downer part belong to the Black Player, and the white player just has some stones in the black territory?

To make it more clear what i mean, look at the second picture. what about the down part here? is the whole black territory just ruined by the little white territory? or does just the white territory count and the black player should try to capture the white stones?

Also, what determines the boundaries of a territory? Is white just the 4 free places in the down right corner? Why isn't the exanct opposite of the 4 places a territory surrounded by the white stones as well, if you combine them with the walls? So everything except the 4 stones and the 4 free places..

Sorry for the confusing questions, but i am a confused guy.

Thanks so much!

Alex

Polama · Post by **Polama** » Fri Nov 21, 2014 12:52 pm

We usually define territory as unfilled points that are surrounded only by living stones of one color and the edges of the board. So in your first case, the question is: is white alive (I'd say "definitely", but you can play it out in a game if you aren't sure). So that makes the bottom his.

Now, the game is only over if both players pass, white has so much area, black could try to go underneath and create a living group there. With experience you can look at a spot and say "I can invade" or "there's no point even trying", at the beginning don't be afraid to try. If black plays in the bottom area and makes a living group, white will have to share the territory with him. If black tries and dies, then white gets to keep the bottom.

In your second case, we again ask: is white alive? This is a little trickier, so black and white might want to fight more and find out, but certainly white should be able to live. The four spots in the corner are surrounded only by white, so that's 4 points for him. The area at top is surrounded by black, so that's points 65 points for him. The bottom though? The bottom now has living white and black stones next to it. So that's nobodies territory, we call it "dame". That's a lot of territory for nobody to claim, so what should happen now is that black and white fight to close off portions of the bottom to just be their own.

yoyoma · Post by **yoyoma** » Fri Nov 21, 2014 2:23 pm

ThataintChessisit wrote:To make it more clear what i mean, look at the second picture. what about the down part here? is the whole black territory just ruined by the little white territory? or does just the white territory count and the black player should try to capture the white stones?

It's a war. If someone comes in "your" territory, kill'em! If you can't kill'em, then it wasn't your territory.

DrStraw · Post by **DrStraw** » Fri Nov 21, 2014 3:07 pm

From any intersect follow along lines on the board. If you hit only stones of one color then the point belongs to that color. This is clearly the case in your first example but not in the second. It is as simple as that.

The problem comes when one side places a stone in what appears to be the other's territory, say black places a stone on the lower half of the board. In this case the rule above says it is no longer white's territory. But white will respond by trying to capture the stone. If he is able to do so then it once again becomes white's territory. If he is unable to do so then it was never really his territory in the first place.

At this point we run into the issue of scoring. Under Japanese rules white could lose points by doing this, but under Chinese rules he will not. If you don't know the difference look up the different rules set in Sense's library. For beginners learning to play in isolation it is often better to score using Chinese rules until you understand life and death better so that resolving these issues will not cost anything. But most of the world outside of China uses Japanese rules so you need to learn them eventually.

Abyssinica · Post by **Abyssinica** » Fri Nov 21, 2014 3:54 pm

yoyoma wrote:
ThataintChessisit wrote:To make it more clear what i mean, look at the second picture. what about the down part here? is the whole black territory just ruined by the little white territory? or does just the white territory count and the black player should try to capture the white stones?

It's a war. If someone comes in "your" territory, kill'em! If you can't kill'em, then it wasn't your territory.

In my games. the entire board is my territory.

DrStraw · Post by **DrStraw** » Fri Nov 21, 2014 4:45 pm

Abyssinica wrote:
yoyoma wrote:
ThataintChessisit wrote:To make it more clear what i mean, look at the second picture. what about the down part here? is the whole black territory just ruined by the little white territory? or does just the white territory count and the black player should try to capture the white stones?

It's a war. If someone comes in "your" territory, kill'em! If you can't kill'em, then it wasn't your territory.

In my games. the entire board is my territory.

Well, at least until W plays his first move.

EdLee · Post by **EdLee** » Fri Nov 21, 2014 6:54 pm

Hi Alex,

You asked very common, standard questions for your phase of understanding.

It's also helpful to use diagrams and/or SGF files to discuss variations:

An empty 13x13 diagram:

Click Here To Show Diagram Code: [go]$$B $$ ----------------------------- $$ | . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . | $$ | . . . . . . , . . . . . . | $$ | . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . | $$ ----------------------------[/go]

An empty 13x13 SGF:

Suppose we continue from your second board as follows:

Click Here To Show Diagram Code: [go]$$W all Passes $$ ----------------------------- $$ | . . . . . . . X . . . . . | $$ | . . . . . . . X . . . . . | $$ | . . . . . . . X . . . . . | $$ | . . . . . . . X . . . . . | $$ | . . . . . . . X . . . . . | $$ | . . . . . . . X . . . . . | $$ | . . . . . . , X . . . . . | $$ | . . . . . . . X . . . . . | $$ | . . . . . . . X . . . . . | $$ | 2 4 6 8 . . . X . . . . . | $$ | O O 1 0 . . . X . . . . . | $$ | . . O . . . . X . . . . . | $$ | . . O . . . . X . . . . . | $$ ----------------------------[/go]

Continued:

Click Here To Show Diagram Code: [go]$$Wm11 both Passes $$ ----------------------------- $$ | . . . . . . . X . . . . . | $$ | . . . . . . . X . . . . . | $$ | . . . . . . . X . . . . . | $$ | . . . . . . . X . . . . . | $$ | . . . . . . . X . . . . . | $$ | . . . . . . . X . . . . . | $$ | . . . . . . , X . . . . . | $$ | . . . . . . . X . . . . . | $$ | . . . . . . . X . . . . . | $$ | X X X X . . . X . . . . . | $$ | O O O X . . . X . . . . . | $$ | . . O 2 . . . X . . . . . | $$ | . . O 4 . . . X . . . . . | $$ ----------------------------[/go]

Given the above board, can you confirm that the White corner is dead ?

See also post 4, DrStraw's reply.

Abyssinica · Post by **Abyssinica** » Fri Nov 21, 2014 7:17 pm

DrStraw wrote:
Well, at least until W plays his first move.

Then I try to kill him. :blackeye:

lightvector · Post by **lightvector** » Fri Nov 21, 2014 7:32 pm

Echoing many of the previous answers:

* A region of the board is your territory if you can kill every possible stone your opponent has played or might play there, without ultimately being killed yourself.

* In practice, people don't actually capture every "dead" stone in their territory because it's obvious to both players already and going through the motions of actually capturing is boring (and because a common ruleset in use actually penalizes you for doing so).

* But it may not be obvious if you're a beginner. So: "When in doubt, play it out." It's only the opponent's territory if he can kill you, so if you disagree or aren't sure, just play some stones in there. If he can kill you (or you reach a point where it's obvious that nothing of yours will survive there, even if he hasn't actually captured every stone), then it's his territory. If you do survive, then it wasn't his territory after all.

Elom · Post by **Elom** » Sat Nov 22, 2014 2:45 am

yoyoma wrote:
ThataintChessisit wrote:To make it more clear what i mean, look at the second picture. what about the down part here? is the whole black territory just ruined by the little white territory? or does just the white territory count and the black player should try to capture the white stones?

It's a war. If someone comes in "your" territory, kill'em! If you can't kill'em, then it wasn't your territory.

A long, long time ago, this is what some of the the first WeiQi players would have said. But after the Japanese expanded upon the serene, divine nature of the game, they began to take the lead internationally. That was a long time ago ...

http://baduktv.kr/baduk/user/userNews

Think of it like water. If I go into a pool and place a skeleton of a box in the corner, I intend to close off that area of water:

Click Here To Show Diagram Code: [go]$$B 19x19 diagram $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . O . . O . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

When I put wrapping foil around that shell, it becomes certain.

Click Here To Show Diagram Code: [go]$$B 19x19 diagram $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . O O O O . . . . . . . | $$ | . . . . . . . O . . . . O . . . . . . | $$ | . . . . . . . O . . . . O . . . . . . | $$ ---------------------------------------[/go]

shapenaji · Post by **shapenaji** » Sat Nov 22, 2014 8:24 am

ThataintChessisit wrote:Heyall,

An important part of this game is that it ends with agreement, if you agree that all your white stones are dead, then certainly, the whole thing is black's territory.

If there is a disagreement though, after you've both decided the game is over, you can prove that something is alive or dead. This is where area-scoring helps http://senseis.xmp.net/?AreaScoring (there's no cost to the proving step.) It's still doable with japanese rules, but, officially at least, it can get complicated.

There are rarely disagreements during the scoring of high level play though. They generally involve strange endgame patterns, and aren't worth more than a point.

ThataintChessisit · Post by **ThataintChessisit** » Mon Nov 24, 2014 11:50 am

Wow you are really the nicest people on earth! All your answers helped a lot, I think i understood it now. Thanks, you brave soldiers :salute:

ThataintChessisit · Post by **ThataintChessisit** » Mon Nov 24, 2014 1:13 pm

Hey so we played another game right now, but we came to a point which confused us again. Saying we have got the situation as it is shown in the first picture. that would be 5 points for black. but if white places this one stone inside of the territory, black can't remove it and is therefore worthless? is that true?

edit: first and second picture are swapped for some reason

yoyoma · Post by **yoyoma** » Mon Nov 24, 2014 1:52 pm

ThataintChessisit wrote:Hey so we played another game right now, but we came to a point which confused us again. Saying we have got the situation as it is shown in the first picture. that would be 5 points for black. but if white places this one stone inside of the territory, black can't remove it and is therefore worthless? is that true?

Why do you say black can't remove it? The white stone looks doomed to me.

Polama · Post by **Polama** » Mon Nov 24, 2014 2:24 pm

There are two main ways to count the score: they almost always give the same winner, so it's a matter of preference which you use.

The first choice is to agree at the end of the game which stones are dead, and remove them from the board. If you can't agree, just keep playing until they're captured. You give back captured stones. Then you count all the territory, and all the stones on the board. This is called "area scoring". If there are no empty spots (dame) in between the groups, you can just count one players score, and then subtract that from the total number of points on the board (361 for 19x19, 169 for 13x13, 81 for 9x9). If black has 30 points of territory and 60 stones on the board in a 13x13 game, then he has 90 points. Since there are 169 points on the board, that would mean white has the other 79. This is called "area scoring"

The second choice is "territory scoring", and is a little more common. When the game is over, you agree with your opponent about which stones are dead, and remove them. This time you don't give them back, you keep them as "prisoners". Then you add the number of prisoners to the amount of territory you have. This time, you can't tell how many points there will be, so you have to count black and white separately. Still, not having to count all of the stones is often faster. With this method of scoring, having to capture dead stones is bad for you, because you have to fill in your own territory (with area scoring, it doesn't matter because territory and stones are worth the same). So it's more important that both sides just agree, without playing out actually surrounding the stones (they still become prisoners if you both agree they're dead, without playing all their liberties). If there is a disagreement, the best rule is to play it out to decide if the stones are dead, but then remove all the stones you just added. It can be tricky to remember the original position, though. Another option is to just agree to both play inside the area in question: you add a stone to your territory, which costs a point. But then your opponent adds another dead stone, so that's +1 prisoner! Then you add a stone and lose a point, and he adds a dead stone and you get +1 prisoner. In the end, if you play the same amount of stones inside the territory, the score won't change but you can confirm that a stone is captured.

It's unfortunate this becomes complicated in the general case, because almost always it's clear if something is dead or not.

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