A simple question, which I should know the answer to, but it has never been an issue before.

Click Here To Show Diagram Code

[go]$$Wc 19x19 board
$$ ---------------------------------------
$$ | . . . . . . . . X . . . . . . . . . . |
$$ | X X X X X X X X X . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |[/go]

Here, Black is obviously alive, and has 8 points of territory.

If White plays on D19, and Black has to kill the invasion, Black will lose 2 empty points, but gain 1 prisoner. Net effect, loses 1 point.

So, if White does play inside the group, what is the procedure? Is the onus on White to prove he can live there, or on Black to prove he can kill?

_________________
Regards,

Peter

This is an annoying niggle in the standard rules everyone uses. As you say, it's a little difficult to make sense of it.

To answer it, lets first remember how the game ends - both players pass when they think there are no more moves left worth playing. That is, they don't want to play in their own territories as this would reduce their points, and they don't want to play in their opponents territories as they reckon this is just giving their opponent captures!

So, both players pass. The next stage is that the players agree between themselves which stones on the board are dead, if any. This is rarely controversial! By this, I mean stones like one white might play in your problem - it's on the board, but black doesn't need to play any more moves because no matter what white does, black believes he can capture it anyway.

After this, the rest of the counting follows...place prisoners in opponent's territory, rearrange, count.

So, back to your problem. The answer is in the stage where the players agree what stones are dead. If this happens in a game, you can simply ignore white's move and any subsequent moves as long as you like...though of course it's worth playing if white puts enough down to be a problem! At the end of the game, after both players pass, then you can claim they are dead and if your opponent disagrees you can play it out. If you successfully prove it, the playing it out doesn't count against your score, it's separate from the main game.

So overall, you don't have to play to capture all the stones because it merely suffices to be able to prove at the end of the game that they are dead.

There are other rulesets that make this process much neater. The main difference is that we can use area scoring, where instead of getting 1 point for each territory place and 1 point for each prisoner you get 1 point for each territory space and 1 point for every stone you have on the board and 0 points for each prisoner. This turns out to give the same result margin (disregarding some minor funky bits, but not important to the general idea), but now you can play out the situation without losing points since the counting is done differently.

So if the status of a group is disputed, you perform 2 counts (one with the group as alive, one as dead), then play it out to see which one applies?

_________________
Regards,

Peter

I'm not sure what exact procedure would be required by any particular ruleset. It may not even be well defined. But yes, that's certainly one way of doing it to get the correct answer.

The way I've usually heard it presented is to set up the game position on another board, play it out, then go back to the first one to do the count. Obviously that should give the same result. In practice it doesn't really come up, since once you get the hang of it there's rarely any debate about it. That's not to say you shouldn't if you aren't sure, of course...even professionally there've been some entertaining rules disputes.

If this comes up in a real game, don't be afraid to ask for help - it's often much easier to see if someone more familiar with the system can just show you in real life. I remember having the exact same question and not being able to make sense of it! If you're playing on (say) KGS, the 'Beginners Room' or 'KGS Teaching Ladder' (both under the lessons heading) generally have people happy to help.

You don't do 2 counts, you do 1 with the resolved status. It's useful if you have a spare board as then you can leave the position at the just-had-2-passes-about-to-count stage, copy the position (or just the relevant section) onto the spare board and play it out to work out if it is dead or not, and then count on the main board (rather than having to memorise the position and rewind).

I've never actually done this though as this is a problem in theory but never in practice other than for confused beginners.

I'm not an expert, but I think the AGA rules are very specific. I posted on the endgame procedure with reference to the AGA rules.

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This is where Chinese rules (area scoring -- empty points plus alive stones) can perhaps be more beneficial for beginners than Japanese rules (territory scoring -- empty points minus prisoners/dead stones)

lets look at some examples on a smaller board -- WARNING: There's math involved (but its simple math, take time to read it, I think it'll make sense)

Click Here To Show Diagram Code

[go]$$Bc 5x5 board
$$ -------------
$$ | . . . . X |
$$ | X X X X X |
$$ | O X . O X |
$$ | O O O O O |
$$ | O . . . . |
$$ -------------[/go]

Here both black and white have played the same number of moves with 8 alive stones on the board, and each have 4 points of territory, with an unfilled dame point left. Assume 0 captured prisoner each.

Area Scoring

• Black = 8 + 4 = 12
• White = 8 + 4 = 12

result: 12 - 12 = 0 / Jigo (tie)

Territory Scoring

• Black = 4 - 0 = 4
• White = 4 - 0 = 4

result: 4 - 4 = 0 / Jigo


But now suppose black is not happy with just a tie, and still want a win, and wonders if he can kill white.

Click Here To Show Diagram Code

[go]$$Bc 5x5 board
$$ -------------
$$ | . . . . X |
$$ | X X X X X |
$$ | O X . O X |
$$ | O O O O O |
$$ | O . 1 a . |
$$ -------------[/go]

Now if white doesn't answer at a, black will play another move at a and will indeed kill all of white's stones. The whole board will belong to black -- no need to count that score.


But if white does answer...

Click Here To Show Diagram Code

[go]$$Bc 5x5 board
$$ -------------
$$ | . . . . X |
$$ | X X X X X |
$$ | O X . O X |
$$ | O O O O O |
$$ | O . 1 2 . |
$$ -------------[/go]

Now can't live on its own, its dead and we remove it from the board as a prisoner at the end.

Why? Doesn't white have to actually capture it? No, and lets using Chinese area scoring to see why not...

If we don't capture it (but assume its dead and remove it as a prisoner)...
Area Scoring

• Black = 8 + 4 = 12
• White = 9 + 3 = 12

result: 12 - 12 = 0 / Jigo (tie)
Black will still only have 8 stones on the board and 4 points of territory, while white will have 9 stones on the board but only 3 points of territory. The score is unchanged.


Now lets force capture it with (black passed).

Click Here To Show Diagram Code

[go]$$Bc 5x5 board
$$ -------------
$$ | . . . . X |
$$ | X X X X X |
$$ | O X . O X |
$$ | O O O O O |
$$ | O 4 . 2 . |
$$ -------------[/go]

Area Scoring

• Black = 8 + 4 = 12
• White = 10 + 2 = 12

result: 12 - 12 = 0 / Jigo (tie)

Again black will still only have 8 stones on the board and 4 points of territory, while white now has 10 stones on the board and only 2 points of territory. The score is still unchanged.


This is how it should be. Stones that are not alive should not affect the score, and it doesn't matter if you actually capture them, or just simply remove them at the end -- the score won't change


But if we count those two positions using Territory scoring...
In the first example where we just remove the known dead stones
Territory Scoring

• Black = 4 - 1 = 3
• White = 3 - 0 = 3

result: 3 - 3 = 0 / Jigo

White has one "captured" black stone that is subtracted from Black's territory, and white has one less territory because he had to play to defend his group.

Whoa, look at that, the score is still unchanged. This matches the earlier results using Area scoring. This is still as it should be -- dead stones don't affect the score.


But in the last diagram, white played an extra unnecessary move to actually capture an already dead stone.

Territory Scoring

• Black = 4 - 1 = 3
• White = 2 - 0 = 2

result: 3 - 2 = 1 / B+1

Now black wins by 1 point.


Remember, removing dead stones at the end is only a shortcut to the inevitable -- those stones won't be able to make life on their own anyway. If they could, then you should have played it out.

And as long as your opponent answers your threat, the score won't change, because the prisoners gained cancels out the filled in territory.

But if you make unanswered threats, then you are losing points for each.
Or if you play extra moves to kill already dead stones, then you lose points for each.

Except Chinese rules

Beginners, use Chinese rules and keep playing until your sure those stones are alive or dead.


Tune in next week for: "How filling the dame could have won or lost the game", and "Why AGA pass stones make area and territory scoring the same"

I don't understand people who say area scoring is easier for beginners.

1. The resolution to the end of the game is the same in both cases, as far as beginners are concerned - "if you disagree about dead stones at the end of the game just play it out, but the stones you play won't change the score". The only difference is that the reason it doesn't affect the score in Japanese rules is that you remove the demonstration stones again once everyone understands why the dead stones are dead.

2. Does anyone teach beginners to count zi? Does anyone think it's easy to count up ~180 stones plus territory per side? I am going to say that I've never seen anyone tell a new player to count an area on a physical board.

Because area scoring is easier to understand conceptually, at least for new players. With area scoring, it basically comes down to how much "stuff" you have on the board: easy. With territory scoring, the thought of playing unnecessary stones to reduce your score is stressful and confusing to understand. Your comment about demonstration stones is true, but new players might make unnecessary moves before the game is over.

I learned area scoring first. It's more time consuming, but certainly not difficult. And if you are only counting black, you don't have to count up both sides.

Have you taught any beginners to count zi?

There are lots of ways in which area scoring is easier to think you understand, but harder to actually understand. For example, capturing dead stones in your own territory during the middle of the game - "Well, I need to capture them eventually, and I don't lose points for this since we're using Chinese scoring..."

Sure. It wasn't a problem.


You're right. Chinese counting doesn't solve any of the problems you mention. Those are still lessons the new player has to learn. Eventually, I tell a new player that she needn't bother wasting moves to capture dead stones. Then again, that's not really something I worry too much about at first. First things first: it's more important to make the new player comfortable with the game before worrying about what is and is not an unnecessary move.

I certainly don't think Chinese counting is any more difficult than Japanese counting to understand. For some (many?) new players, area scoring doesn't cause any cognitive hang-ups that seem to crop up with territory scoring -- and if that eases the learning curve, I'm for it.

To be fair, I suppose I should say that when I teach area scoring, I don't typically go into the zi count on the first few games. I just explain that there are 361 points on the board, and whoever can score a majority of those points (i.e., more than 180.5), wins. I also tell them that we can calculate the margin of victory, but that it's not too important at first.

So do you count the board for the new players at first, or just tell them who won?

I don't know if its been changed, but it used to be that the Die Hard tournament every year required participants to use Chinese counting. That was my first experience with it.

Not long after that initial experience, I was playing a casual pick-up game in a public food court with a man who didn't speak English. Shortly into the game he captured some of my stones and just tossed them back into my bowl. Initially I was quite taken aback, but I quickly regained my composure, remembering that I now know how to do Chinese counting


If by "zi" you mean the difference in the number of empty intersections or occupied stones from your opponent -- I call those "points".


Its really easy when done in units of 10.
Set aside one stone for every 10 units, and if you have more that 18 of those, you win.

This is quite a nice example for anyone who's never done it before:
http://senseis.xmp.net/?ChineseCountingExample

I count out black's score so they can see how it all works. It's just that I focus on whether black had more or less than a majority of the points. From there, the new player can easily see how it would be possible to determine the margin of victory if they wanted to. It's never really been a big deal. They've always seemed to be able to pick up on the method fairly easily.

Right, so that's not zi. Half that number (the difference between your area and half the board) is what you calculate with Chinese scoring. (I'm not trying to be pedantic, I don't care whether you call these points or zi - just trying to distinguish between two different ways of counting with area, neither of which I've seen used to teach beginners the game.)


That's how you count zi. Watching someone count zi is like watching a street hustle. Teaching someone to count zi is like teaching an easy magic trick - although Tim, at least, says he does it with beginners after a few weeks of playing the game. -- Is "units of ten" referring to the method you use to keep track of the territory when counting zi, or when counting up the entire board (stones and territory) in a sort of bastardized territory counting? (That's why I asked a two-part question - if you teach a beginner to count area, you need to do one or the other, and I'm not sure which one people think is so easy for beginners.)

I'm confused by your question. I count out the board just like the Chinese counting example linked to above. I do this from the first game onward with new players because it's what I'm personally comfortable with. "Zi" isn't a counting method; it referes to the difference between the count and half the scorable intersections on the board.

The "units of ten" just means that you divide territory and stones into groups of ten. You can place one stone on the side of the board for every ten points while counting. It's just a method of remembering what the count is at for the sake of ease. It's especially useful when trying to remember how much area (i.e., territory) black has before you start counting up stones.

as demonstrated in that example, you do both (at least that's how I learned it)

just like in territory counting, rearrange your open territory into groups/multiples of 10 -- adding or removing stones from your bowl as necessary to make the count even.

then clear all the white stones off the board and arrange remaining black stones into groups of 10.

then count how many 10s you have total.

edit: Tim and I are saying the same thing
Its late and I really should be going to bed now anyway

Sorry, I think my question must have been poorly phrased. The traditional method for counting with Chinese scoring gives a result in zi. That's all I meant by "counting zi". You definitely use this method, I think Xed_over is saying that's what he uses. This is the method I don't think you can teach someone the first time they play (and I think you agree?)

This isn't the only way you could do area scoring, if you agreed with me that counting the board in the Chinese style is a skill you have to learn, but wanted to have a beginner score area anyway. You could also just try to directly count all the stones and territory you have. This is conceptually simple, but much more likely to lead to counting errors than territory scoring (I think we agree on this too?)

sure you can.


the only other method I know of is to use Ing's fill-in counting.

edit: oh, or you could count both black and white, instead of just one or the other.


This is exactly what we're doing, but by rearranging, we eliminate the counting errors.

same as with territory scoring.