Life In 19x19

yoyoma wrote:

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.

To elaborate, it may take three moves to capture it, because the white stone has 3 liberties, but black can capture it. There's no way for white to play so that black can never capture it, so conventionally, black doesn't waste the moves and it's just counted as captured at the end of the game.

The only way for white's stone to be alive would be if black's stones were surrounded and would run out of liberties before white's stone does.

Click Here To Show Diagram Code

[go]$$Bc Example
$$ ------------------
$$ | X a W c X d X O .
$$ | X X W X X X X O .
$$ | b X X O O O O O .
$$ | X X O . . . . . .
$$ | O O O . . . . . .
$$ | . . . . . . . . .[/go]

In this diagram, black can't play A, because he'll only have one liberty at B and white will play there to capture next turn. Black can't play C either, because the right stones will only have one liberty at D afterwards, and white will again capture.

Click Here To Show Diagram Code

[go]$$Bc Example 2
$$ ------------------
$$ | . W . X O . . . .
$$ | X X X X O . . . .
$$ | O O O O O . . . .
$$ | . . . . . . . . .[/go]

In this second diagram, black can capture the marked white stone, but black's stones are dead, because white will eventually be able to fill all the spaces inside (even with black capturing) until black's stones run out of liberties.

Click Here To Show Diagram Code

[go]$$Bc Example 3
$$ ------------------
$$ | . W . X a X O . .
$$ | X X X X X X O . .
$$ | O O O O O O O . .
$$ | . . . . . . . . .[/go]

And finally in this one, black doesn't need to play to capture the marked stone because it is already dead. White will never be able to fill the liberty at A until all the other spaces are filled, but white can't fill the two spaces next to the marked stone, because in taking the second one, he would have no liberties left, and would not be capturing anything to keep this move from being suicide.

Click Here To Show Diagram Code

[go]$$Wc Example 3 continued
$$ ------------------
$$ | O W 1 X . X O . .
$$ | X X X X X X O . .
$$ | O O O O O O O . .
$$ | . . . . . . . . .[/go]

Here, white takes his own last liberty, but black still has one left, so this is an illegal move.

Since it's not always clear when a stone is dead or not, I recommend that if you play with territory scoring (count surrounded empty spaces and captured stones) you not play with passes, but just end the game when you both agree. So long as one player keeps putting stones down, the other one does too. This should result in a sensible game in most cases until you get a better idea of what's dead and what isn't.

skydyr wrote:Since it's not always clear when a stone is dead or not, I recommend that if you play with territory scoring (count surrounded empty spaces and captured stones) you not play with passes, but just end the game when you both agree. So long as one player keeps putting stones down, the other one does too. This should result in a sensible game in most cases until you get a better idea of what's dead and what isn't.

At this point I would not worry too much about the score. Just play all positions out, even if you lose a few points, so that you can see what is capturable and what is not. You will learn pretty quickly once you are exposed to it. Later you don't need to play it out because you will know which stones are dead and you will just remove them.

yoyoma wrote:

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.

How is that? In order to fully surround the white stone, black has to place a stone right + underneath the white stone, which is impossible because in those two spaces, black would have no liberties left...

Also, why would the white stone be dead? It was mentioned above:

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.

ThataintChessisit wrote:

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

How is that? In order to fully surround the white stone, black has to place a stone right + underneath the white stone, which is impossible because in those two spaces, black would have no liberties left...

Not quite! When black plays a stone either to the right or directly underneath the white stone, it has lots of liberties, because it's connected to the other black groups around it.

ThataintChessisit wrote: How is that? In order to fully surround the white stone, black has to place a stone right + underneath the white stone, which is impossible because in those two spaces, black would have no liberties left...

Also, why would the white stone be dead? It was mentioned above:

edit: what lightvector says
here's a diagram...

Click Here To Show Diagram Code

[go]$$B
$$ | . . . X O . . O . O
$$ | . . X X O O . O O .
$$ | . X . X X X O . O .
$$ | X . O X X X X O . .
$$ | . X X . . O . X O .
$$ | . . . X X 1 X X O .
$$ | . . . . O X X . . .
$$ | -------------------[/go]

And the white stone is dead, because it can't prevent itself from being captured.

I think whatever resource you used to learn the rules wasn't clear because you have the wrong idea about how liberties work. Try this site:

http://playgo.to/iwtg/en/

Okay i understood that now, but I still have this one question:

http://playgo.to/iwtg/en/count.html

Here its says that the first board is considered finished, because the black stone, as pictured in the second board would be captured quite quickly. But even if so, wouldn't it shrink down white's territory drastically? Because as he said, stones are not counted as points, so white would be forced to place some stones in its own territory, reducing his points a lot. Do I oversee something here?

ThataintChessisit wrote:Okay i understood that now, but I still have this one question:

http://playgo.to/iwtg/en/count.html

Here its says that the first board is considered finished, because the black stone, as pictured in the second board would be captured quite quickly. But even if so, wouldn't it shrink down white's territory drastically? Because as he said, stones are not counted as points, so white would be forced to place some stones in its own territory, reducing his points a lot. Do I oversee something here?

What he should have said is that the Black stone could be killed, not that it could be captured. In the second diagram the lone Black stone is dead, and after the players have agreed to end the game it is removed without capturing. OC, that means that Black has to agree that the stone is dead.

There are ways of dealing with disagreement, but since you are playing beginner vs. beginner, the easy way is to play by area scoring, which counts both stones and territory, but does not count prisoners. Then White can capture the Black stone, and the score remains the same. White wins by 5 points.

But why would Black disagree with the stone being dead if he could win points, and make a difference on how the end result will be, in some cases maybe even deciding who wins?

ThataintChessisit wrote:But why would Black disagree with the stone being dead if he could win points, and make a difference on how the end result will be, in some cases maybe even deciding who wins?

You need to read up on the difference between Chinese and Japanese scoring. Under Chinese scoring your concerns do not come into play, as the score is not affected. Under Japanese scoring it is, but there is a provision in the rules to back out effects of disputes: the problem, of course, is that beginners may not back out accurately. But the bottom line is that, if played correctly, disputes as you mention do not affect the end result.

think of it as a shortcut.

if the black stone cannot prevent itself from being surrounded/suffocated, then we are just saving ourselves the time and energy of actually surrounding/suffocating it and capturing it.

As Bill says, if we were to use Chinese rules, then the score wouldn't change whether you played it out or not.

Using Japanese rules, if we were to force white to capture the stone without black having to respond, then white would lose points. But at this point, its both courteous and a shortcut -- black can't live, so its considered dead. There's no point in playing it out.

ThataintChessisit wrote:But why would Black disagree with the stone being dead if he could win points, and make a difference on how the end result will be, in some cases maybe even deciding who wins?

You mean why would he agree? The point is that disagreeing would not make any difference in the score. Different versions of territory rules handle the disagreement differently, but they agree with each other except in rare instances. They certainly agree here. The lone Black stone is dead. You can learn such methods if you like, but the easy thing to do is to use area scoring.

... And this long series of discussions is why I think we should just abandon territory scoring entirely. Why do we make this so hard on ourselves?

In any case, as Bill said, use area scoring, a point for each stone on the board, and a point for each empty space. If one side disagrees, resume play.

shapenaji wrote:... And this long series of discussions is why I think we should just abandon territory scoring entirely. Why do we make this so hard on ourselves?

In any case, as Bill said, use area scoring, a point for each stone on the board, and a point for each empty space. If one side disagrees, resume play.

And no more bent 4 controversies.