Life In 19x19 :: Territory Scoring Question

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Territory Scoring Question http://www.lifein19x19.com/viewtopic.php?f=11&t=9652	Page 1 of 1

Author: sabruka [ Mon Jan 06, 2014 2:15 pm ]

Post subject: Territory Scoring Question

Hi everyone. I am new to the game of go, and I think I understand how scoring works. I guess my question is more about strategy.

Suppose the following board is the complete board:

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

Then, by my understanding of territory scoring, black would have 3 points and white would have 0 points in this section. If I were white, then I would play in the middle in order to reduce black's scoring:

Click Here To Show Diagram Code: [go]$$ $$ --------------------------------------- $$ | X X X X X | $$ | X . O . X | $$ | X X X X X | $$ ---------------------------------------[/go]

Black would then need to recapture that area (since both intersections are now neutral), which would result in the following

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

reducing black's score to 1 and, because of the prisoner, reducing white's score to -1. The difference of scores becomes 2 instead of 3 as before. Would this be a good play from white in order to reduce black's score in this area? Or is there something I am not seeing?

Thanks!

Author:	skydyr [ Mon Jan 06, 2014 2:27 pm ]
Post subject:	Re: Territory Scoring Question
sabruka wrote: Hi everyone. I am new to the game of go, and I think I understand how scoring works. I guess my question is more about strategy. Suppose the following board is the complete board: Click Here To Show Diagram Code `[go]$$ $$ --------------------------------------- $$ \| X X X X X \| $$ \| X . . . X \| $$ \| X X X X X \| $$ ---------------------------------------[/go]` Then, by my understanding of territory scoring, black would have 3 points and white would have 0 points in this section. If I were white, then I would play in the middle in order to reduce black's scoring: Click Here To Show Diagram Code `[go]$$ $$ --------------------------------------- $$ \| X X X X X \| $$ \| X . O . X \| $$ \| X X X X X \| $$ ---------------------------------------[/go]` Black would then need to recapture that area (since both intersections are now neutral), which would result in the following Click Here To Show Diagram Code `[go]$$ $$ --------------------------------------- $$ \| X X X X X \| $$ \| X X . X X \| $$ \| X X X X X \| $$ ---------------------------------------[/go]` reducing black's score to 1 and, because of the prisoner, reducing white's score to -1. The difference of scores becomes 2 instead of 3 as before. Would this be a good play from white in order to reduce black's score in this area? Or is there something I am not seeing? Thanks! In your first diagram, black owes a move at the center point in order to make two eyes, so he really only has two points. Once white plays in the center, black can capture him, but is reduced to one eye, so following the last diagram, white can play on the open point and capture all the black stones, since they only have one liberty. More generally, assuming that that is not a complete board and the black stones are independently alive because they are connected to something else, black does not need to play to actually capture the white stone. At the end of the game it is deemed dead and captured because there is no way white can make that white stone alive. As a result, black gets three points for the territory, plus one more for the captured white stone once it is declared dead at the end of the game. In territory scoring, if there is a question about the life and death status after the game is over, you can play it out to see, but the board is returned to the state it was when you both originally decided the game was over if those stones are dead. This can be somewhat confusing, which is why area scoring is often recommended for beginners.

Author: Bill Spight [ Mon Jan 06, 2014 2:36 pm ]

Post subject: Re: Territory Scoring Question

sabruka wrote:

Hi everyone. I am new to the game of go, and I think I understand how scoring works. I guess my question is more about strategy.

Suppose the following board is the complete board:

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

Click Here To Show Diagram Code: [go]$$ $$ --------------------------------------- $$ | X X X X X | $$ | X . O . X | $$ | X X X X X | $$ ---------------------------------------[/go]

Black would then need to recapture that area (since both intersections are now neutral), which would result in the following

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

What you are missing is that if Black plays first,

Click Here To Show Diagram Code: [go]$$B $$ ------------ $$ | X X X X X | $$ | X . 1 . X | $$ | X X X X X | $$ ------------[/go]

Black gets 2 points of territory. But if White plays first,

Click Here To Show Diagram Code: [go]$$W $$ ------------ $$ | X X X X X | $$ | X . 1 . X | $$ | X X X X X | $$ ------------[/go]

White kills the Black stones, and gets 26 points of territory (2 for the two open points, and 24 for the 12 dead stones). It may not be obvious that :w1:

kills, but that can be demonstrated by further play.

Note that White does not have to capture the Black stones in order to kill them. If this is confusing, then you may find it easier to play by area rules, at least at first.

Author: Bill Spight [ Mon Jan 06, 2014 2:45 pm ]

Post subject: Re: Territory Scoring Question

These may help with your intended question.

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

Black has 7 points of territory.

Click Here To Show Diagram Code: [go]$$ $$ ------------ $$ | . X X X . | $$ | X . . X O | $$ | . X X X . | $$ ------------[/go]

Black has 8 points.

Click Here To Show Diagram Code: [go]$$ $$ ------------ $$ | . X X X O | $$ | X . . X O | $$ | . X X X . | $$ ------------[/go]

Black has 9 points.

Click Here To Show Diagram Code: [go]$$ $$ ------------ $$ | . X X X O | $$ | X . O X O | $$ | . X X X . | $$ ------------[/go]

Black has 10 points.

Why that is how territory is scored is lost in the mists of time. Dead stones do not have to be captured.

Author:	skydyr [ Mon Jan 06, 2014 2:52 pm ]
Post subject:	Re: Territory Scoring Question
Bill Spight wrote: These may help with your intended question. Why that is how territory is scored is lost in the mists of time. Dead stones do not have to be captured. My understanding is that originally, there was an assumption or requirement that both players play an equal number of plays. Passing, as a move, did not exist. So long as there are an equal number of plays and dame are filled, extra stones thrown into an area where they can't live are balanced out by the point the opponent loses by filling territory or playing a stone that dies as well.

Author:	sabruka [ Mon Jan 06, 2014 3:34 pm ]
Post subject:	Re: Territory Scoring Question
Thank you everyone for your replies. I feel like my understanding of the game got better I have a follow-up question, since I haven't yet really completely understood the concept of alive vs dead. In my understanding, stones that are alive are stones that cannot be captured, such as stones connected to two true eyes, and stones that are dead are stones which can never be made alive for various reasons. Is that true? Thanks!

Author:	Bill Spight [ Mon Jan 06, 2014 4:33 pm ]
Post subject:	Re: Territory Scoring Question
skydyr wrote: Bill Spight wrote: These may help with your intended question. Why that is how territory is scored is lost in the mists of time. Dead stones do not have to be captured. My understanding is that originally, there was an assumption or requirement that both players play an equal number of plays. Passing, as a move, did not exist. So long as there are an equal number of plays and dame are filled, extra stones thrown into an area where they can't live are balanced out by the point the opponent loses by filling territory or playing a stone that dies as well. Thing are not altogether clear. There is even a game record that states that each player has made so many plays, but Black has played one more stone than White. IIRC, -- the gogod site is down, so I can't check --, the oldest known description of go rules says that each player makes the same number of plays, but also says that play continues until the board is filled. See viewtopic.php?p=82898#p82898 . The following 3x3 game illustrates the problem with that description. Click Here To Show Diagram Code `[go]$$ $$ --------- $$ \| 6 4 7 \| $$ \| 2 1 3 \| $$ \| . 5 . \| $$ ---------[/go]` White has no play on the board, but surely the game does not end here with Black ahead by one (or one move earlier with a tie). It seems that there could be forced passes.

Author:	Bill Spight [ Mon Jan 06, 2014 4:48 pm ]
Post subject:	Re: Territory Scoring Question
sabruka wrote: Thank you everyone for your replies. I feel like my understanding of the game got better I have a follow-up question, since I haven't yet really completely understood the concept of alive vs dead. In my understanding, stones that are alive are stones that cannot be captured, such as stones connected to two true eyes, and stones that are dead are stones which can never be made alive for various reasons. Is that true? Thanks! Generally speaking, you can consider a stone to be alive if the opponent cannot capture it, playing first, and you can consider a stone to be dead if it can be captured, even if the opponent plays second. But there are some ordinary exceptions. Click Here To Show Diagram Code `[go]$$ $$ ------------ $$ \| . X . O O \| $$ \| X X O B O \| $$ \| . X O . O \| $$ ------------[/go]` For instance, here the stone is considered to be alive, because if White captures it, White is still dead. There are, in fact, some rare and strange situations, called rules beasts, in which different sets of rules disagree about whether stones are alive or dead. As a practical matter, under area scoring you can play on until there are no dead stones on the board, or until both players agree on which stones are alive or dead.

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