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 Post subject: Why fill in neutral territory?
Post #1 Posted: Mon Nov 21, 2016 5:22 am 
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Say a game has ended by both players passing, ended by agreement, why are any neutral points of territory filled in when doing this can result in atari or further issues?
Surely in that case the outcome may have been different depending on which player filled in that particular point, so the order and placement of stones is important and therefore the game hasn't ended and could result in a change in score?
My real question is why fill them in at all if issues can arise? Why not use, say, red stones to fill neutral points in and go from there?

Very new player, so the answer may be obvious but eludes me at the moment.


Last edited by Screature on Mon Nov 21, 2016 5:24 am, edited 1 time in total.
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Post #2 Posted: Mon Nov 21, 2016 5:24 am 
Judan
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Hi Screature,

In Area Scoring, even the stones in neutral area count toward the score.

Otherwise, it's still good habit to fill in the neutral areas --
because, sometimes ( but not always ),
things change with the shortage of liberties.

In other words, it's important for both players to mentally make sure each and every "neutral" point is indeed neutral --
if it can change the score, then it matters --
regardless of the scoring system.

Example: in the NHK YouTube TV tourney games,
they use territory scoring,
but the pros still fill in the neutral points at the end,
before counting -- it's good habit.

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 Post subject: Re: Why fill in neutral territory?
Post #3 Posted: Mon Nov 21, 2016 5:30 am 
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Ah sorry I should have been more specific, I meant in territory scoring!
Considering filling in the neutrals in territory scoring could change the score, how do players choose who fills in first or where?

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Post #4 Posted: Mon Nov 21, 2016 5:34 am 
Judan
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Hi Screature,

Here's an example of territory scoring,
and they still filled in the neutral points:
Quote:
how do players choose who fills in first or where?
After the final non-neutral point is filled, the next player naturally starts to fill in a first neutral point.

From what I've observed, the Japanese pros will generally not play a neutral point that's also sente (e.g. pushing through a bamboo joint which cuts off a non-live group, or an atari, etc. -- they let the opponent voluntarily connect ), simply out of courtesy.

For casual games, in territory scoring, you are not required to fill in the neutral points. But for the reasons given -- important mentally to double check each and every point ; also to make the actual scoring phase cleaner, easily -- I recommend you fill in the neutral points.
Quote:
red stones to fill neutral points
- In general, non-Black-or-White stones are not included in a standard set of stones.
- No need to introduce an extra color; just fill in with the normal B and W stones.

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 Post subject: Re: Why fill in neutral territory?
Post #5 Posted: Mon Nov 21, 2016 5:56 am 
Oza

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If the neutral points cause an atari or require some other action from the opponent then they are not really neutral. That means the game is not over.

It is common for beginners to both pass when there are still points left on the board. Sometimes there are genuine points where there is something to be gain. At other times there are point like you describe, where nothing is really gained by playing them but which require a protective move from the opponent. So by not playing those the opponent does not end up playing a protective move and so gains an unwarranted point.

Experienced players are aware of the need for these protective moves and will make them before being forced to do so. Inexperienced players will not always see them until the neutral points are filled. Until the advent of online go this was not an issue because all neutral points had to be filled in order to do the counting. But now, where the computer counts for you, there has been a tendency to avoid this step and it can be confusing for people until they have a certain level of experience. I have even seen dan players passing without making all necessary protective moves.

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 Post subject: Re: Why fill in neutral territory?
Post #6 Posted: Mon Nov 21, 2016 6:06 am 
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Hi Screature,

Just to supplement and illustrate what has already been said.

It is important to understand that, given optimal play by both players, filling the neutral points doesn't really change the score (even if to a beginner it may seem like they do). For instance, in the following diagram, it may seem that black has eleven points...
Click Here To Show Diagram Code
[go]$$c
$$ ----------
$$ | . . . .
$$ | O O . .
$$ | . O O .
$$ | X X O .
$$ | . X O O
$$ | . . X O
$$ | . . X O
$$ | . . X O
$$ | . . X O
$$ | . . X O
$$ | X X X O
$$ | O O O O[/go]


...however when the neutral point at a is filled, the three black stones can be captured if white plays at b. In this case, black should not fill the neutral point a (unless he wants to lose quite a few points!). Later, when white plays at a, black has to protect his weakness by playing b. Now black's territory is ten points. But, it is important to understand that this does not really mean that black's territory has been reduced from eleven to ten points and that the score has changed. Both players knew (or should have known) beforehand that b would have to be filled and that it was not a point to start with.
Click Here To Show Diagram Code
[go]$$c
$$ ----------
$$ | . . . .
$$ | O O . .
$$ | a O O .
$$ | X X O .
$$ | . X O O
$$ | . b X O
$$ | . . X O
$$ | . . X O
$$ | . . X O
$$ | . . X O
$$ | X X X O
$$ | O O O O[/go]

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Post #7 Posted: Mon Nov 21, 2016 6:18 am 
Judan
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Hi Screature,
Click Here To Show Diagram Code
[go]$$
$$ ---------------------
$$ | . . . . . X a O . |
$$ | X X X X X X X O . |
$$ | O O X O O O X O . |
$$ | . O b O . O X O . |
$$ | O O c O O O X O . |
$$ | X X X X X X X O . |
$$ | . . . . X O O . . |
$$ | . . . . X O . . . |
$$ | . . . . X O . . . |
$$ ---------------------[/go]
From what I've observed, at least from the NHK videos:
given this example board, if it's Black's turn,
and B has a choice ( between (a), (b), (c) ),
Black would play (a), and let White voluntarily connect at (b) or (c).
Just out of courtesy.

Conversely, if it's White's turn, W would connect at (b) or (c),
rather than wait for (or force) Black to try to push through the bamboo joint.

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 Post subject: Re: Why fill in neutral territory?
Post #8 Posted: Mon Nov 21, 2016 6:22 am 
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Brilliant responses, thank you! Plenty of new info to digest and another avenue to learn :tmbup:

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 Post subject: Re: Why fill in neutral territory?
Post #9 Posted: Mon Nov 21, 2016 10:05 am 
Judan

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Screature wrote:
Say a game has ended by both players passing, ended by agreement, why are any neutral points of territory filled in when doing this can result in atari or further issues?


That is why. :) So-called "neutral points" may not actually be neutral. Your example of atari is to the point. Suppose that you make a play that puts some of my stones in atari, threatening to take them unless I connect, can I say you can't play there, it's a neutral point? Of course not. The rules of go allow you to play anywhere, except for the ko or superko rule or self-sacrifice (under most rules). "Neutral points" are not an exception.

If filling in a so-called neutral point causes issues, then technically the players have passed before the game is over. If your filling a neutral point forces me to connect some stones or lose them, then I don't get to call the point I filled to make the connection my territory. So if your pass allows me to count that point as territory, your pass is a mistake.

It is true that experienced players may stop play when filling a "neutral point" may force the other player to make a protective play, but then they fill both the "neutral point" and the protective play before counting the game. If they disagree about whether a protective play is necessary, then they reopen play.

Even experienced players may not know if a protective play is necessary. Beginners often do not know. That is why, IMHO, players below the rank of 9 kyu should always fill all the neutral points before passing. :)

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Post #10 Posted: Mon Nov 21, 2016 10:13 am 
Judan

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EdLee wrote:
Example: in the NHK YouTube TV tourney games,
they use territory scoring,
but the pros still fill in the neutral points at the end,
before counting -- it's good habit.


It's not just a good habit. The Japanese rules do not allow territory to be counted in a region unless all the neutral points next to that region are filled.

----
Edit:For instance, in Shenoute's diagram:

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


Unless "a" is filled, Black has no points of territory on the side, nor does White in the corner. :D
----

When the most recent Japanese rules were written, it was the custom among Japanese pros to end play with neutral points unfilled, and then to fill them informally before counting the score, and the rules were written in such a way as to allow that custom to continue. However, in recent years it has not always been clear whether "neutral points" were filled informally or during play, and "accidents" have happened. So now, as I understand, the pros generally take care to fill all the neutral points during play. :)

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This post by Bill Spight was liked by: Shenoute
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 Post subject: Re: Why fill in neutral territory?
Post #11 Posted: Mon Nov 21, 2016 11:06 am 
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Shenoute wrote:
Hi Screature,

Just to supplement and illustrate what has already been said.

It is important to understand that, given optimal play by both players, filling the neutral points doesn't really change the score (even if to a beginner it may seem like they do). For instance, in the following diagram, it may seem that black has eleven points...
Click Here To Show Diagram Code
[go]$$c
$$ ----------
$$ | . . . .
$$ | O O . .
$$ | . O O .
$$ | X X O .
$$ | . X O O
$$ | . . X O
$$ | . . X O
$$ | . . X O
$$ | . . X O
$$ | . . X O
$$ | X X X O
$$ | O O O O[/go]

[...] Now black's territory is ten points. But, it is important to understand that this does not really mean that black's territory has been reduced from eleven to ten points and that the score has changed. Both players knew (or should have known) beforehand that b would have to be filled and that it was not a point to start with.


Actually, the official text of the japanese rules has always said that, left as it is, in this position, Black has not eleven points.

It's a shady part of the japanese rule.
From 1949 to 1989, the official territory points of Black were 10. But since 1989, they are 0 as long as the neutral point is not filled (and obviously 10 once the neutral point is filled and Black has connected).
Another extremely confusing point is whether there should be one point of territory inside a ko that is left open at the end. In short, the answer is no, but it is practically impossible to find a part of the rules, old or new, that clearly states so, at least in their available english translations.

These problems have given nightmares to programmers who want to develop go software. For this reason, AlphaGo plays in chinese rule only.
And when a question of this kind arises in kgs, an admin must connect and modify manually the final score according to the real japanese rule. CGoban can't count it right. It happened to me once in a position with a two-step mandatory connection at the end.

In conclusion, this is just a matter of convention. The japanese tradition has always considered mandatory to solve all positions of this kind before ending the game.

But writing a clear ruleset including this feature is so problematic that go federations worldwide seem to progressively abandon the japanese rule in favor of the AGA rule.

China first stopped using the japanese rule in 1975, and used a more complicated way of counting the score (stones + territory instead of territory minus prisoners), but with a much simpler rule, soon followed by New Zealand and the Ing foundation.
Later, in 1991, the american federation introduced pass stones with their AGA rule, so as to eliminate these problems without complicating the process of counting the score for the players.
It was followed by the french federation in 1993 and the british one in 2008.
In 2015 (if I'm not mistaken), the European Go Congress adopted the AGA rule too.

Another solution would have been to do just as you suggest : White didn't fill the neutral point, thus Black has got eleven points.
But it is not as easy as it seems, because in other kind of positions, a complex process is still needed to clearly define the score (look for the "simplified japanese rule", that does just that).


This post by Pio2001 was liked by: Shenoute
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