The point that I find strange in button go is not its complications. In fact, I think that button go is ok with requirement 1 : novice players can follow the instructions without problems and score their game (maybe it would be better to remove the life and death consideration, like in the french rule, but that's not a problem).

What bothers me is that it is neither an area rule, nor a territory rule. Its true meaning is that it is an "area plus button" rule.

Practically, I am completely lost in front of a question like "should I take the ko or the button" ? The ko is said to be worth 1/3 of a point, and the button 1/2. So I should rather take the button. It is worth more.
But wait, the core rule is area, so the dame are all worth 1 point, and the ko is more like 1 + 1/3, so I should rather take the ko instead of the button.
But wait, all these are approximation, I'd better read the sequences to be sure. But, OMG, should I count territory + 6.5 komi + pass stones, or area + button ?

But maybe my point of view is biased to begin with, because I must confess that I have always loved area scoring and hated territory scoring.
I must admit that it might explain my reluctance in front of button go, or even my inability to understand its merits.

For me, area is something that can be seen on the board. Territory can't, because territory actually means territory plus prisoners plus dead stones.

By the way, in my sgf, I can see that in all cases that I have considered, button go is equivalent to territory scoring, but with one point of territory inside the ko, if it had been left open !

Wouldn't it be easier then to use the Simplified Japanese Rules ? If I understand them properly, they also grant one point of territory inside the last ko, if it stays open, and they look quite correct to me, I mean, compared to the Japanese 1989 or Japanese 1949 rules.

Under the Simplified Japanese Rules for one basic endgame ko stone remaining unconnected, if its defender starts the analysis by connecting it, it is independently alive and its empty intersection territory. If the attacker starts the analysis and wins the ko fight, the ko stone is not independently alive and the empty intersection not territory.

Right.



It is a hybrid of area and territory rules. The score is typically the same as that by a form of territory scoring, but area rules allow questions of life and death and kos and superkos after the last dame has been filled to be settled by play.

The easiest way to implement button go is by adding a token worth ½ pt. to area rules. Implementing it via territory rules involves passing prisoners between the players.



This sounds confusing to me.



I am not sure what you are asking for. You have verified the equivalence of button go by area and territory scoring for typical situations. Do you want a more rigorous explanation? Or are you asking for something else?

Several years ago on the ancestor of this site I posted a fairly extensive treatment of button go, covering a variety of situations. Unfortunately, those notes got clobbered in the transition and are unrecoverable.

On the assumption that you want an explanation of why area button go and territory button go produce the same results, here is a start.

What is the basic difference between territory and area scoring? Black plays first and if Black gets the last board play at the dame stage, she will get one more point by area scoring than by territory scoring. Depending on other differences between the rules, such as counting territory in seki or not, and different ko or superko rules, there may be other differences, but this is the basic one.

Is there a way of modifying area scoring so that it does not matter who gets the last dame? Yes, there is. Each dame gains 1 point, so adding a play that is worth ½ of that, i.e., ½ pt., will do the trick. So let there be a token worth ½ pt. that a player can take. For instance, suppose that Black is to play when all that is left are dame. Then Black will gain ½ pt., no matter who gets the last dame. If White gets the last dame, so that each play has gotten the same number, Black will take the token (button) and gain ½ pt. If Black gets the last dame, and has gained 1 pt. against White, White takes the button, reducing Black's gain to ½ pt. So the area result will be the territory score + ½ pt. for Black.

What if we use territory scoring? AGA rules do that using pass stones. In that case the button is worth -½ pt., since a play by territory scoring gains 1 pt. less than by area scoring. Can we simplify that method? Yes, we can. Herman Hiddema came up with the idea of adding a second button. At first, that sounds like an additional complication, but in the end it allows us to simplify.

At the end of the game by AGA territory scoring, the players pass and each pass costs 1 pt. The current AGA rules require White to make the last pass. Is there a way to modify the rules so that it does not matter who makes the last pass? That would allow us to do away with the last pass by White rule, which is still puzzling to some players, and even objectionable to some, and is a complication. Yes, there is. We add a last play at the end that loses only ½ pt. instead of 1 pt. Then it does not matter who makes the last pass. The reasoning is the same as having the ½ pt. button means that it does not matter who gets the last dame.

Here comes the simplification. If the player who took the button also gets the last pass, the result for that person is -½ - ½ = -1, i.e., the same as handing over 1 prisoner. So let that person hand over a prisoner when she takes the button, and if she also makes the last pass, let that pass be for free. If the person who took the button is different from the one who gets the last pass, the result for that person is -½ + ½ = 0, the same as if she hands over a prisoner when she takes the button, and her opponent hands over a pass stone on the last pass. Voila!

Edit: OC, the territory rules produce an integer result, so we have to us komi worth ½ pt. less to make the two results the same.

_________________
The Adkins Principle:
At some point, doesn't thinking have to go on?
— Winona Adkins

Visualize whirled peas.

Everything with love. Stay safe.

That's because the button was taken with the ko ban in effect. The result would be different for the Go Seigen-Iwamoto game, because Go Seigen filled the last dame with the ko ban in effect. In that case you don't count the open ko point as territory.

_________________
The Adkins Principle:
At some point, doesn't thinking have to go on?
— Winona Adkins

Visualize whirled peas.

Everything with love. Stay safe.

I think the biggest obstacle in wider acceptance of button go is simply that its benefits are not enough for the complications. Even pass stones - a simpler change that solves important problems - only gained narrow support (compared to Japanese/Chinese/Korean rules).

One may think a tiny extra rule is a small change, and players can be expected to learn and accept it. This is not true. Not (for example) for the majority of players who only have a rough idea of rules. And particularly not for Japanese/Korean, since territory scoring actually allows them to play the main game up to the first stop without any extra rule (besides the basics one learns as a beginner). This advantage is SO HUGE that it seems unreasonable to expect them to give this up.

For Chinese/area rules (which need some rule tricks anyway, even in the main game) it may be a bit easier, especially if the change can be formulated as a tiebreaker instead. So komi=7, ties are possible, but IF a tournament prefers to avoid them, there can be an optional extra rule with similar effect (like fewer stones played wins ties - iirc something like this was discussed in an older thread).

IMHO, that is the main point. Currently we have two different forms of weiqi that are very similar to each other. For international competition with players who are used to one or the other, it would be good to have a hybrid form that combines both. Button go does that.



As a rule, correct play by button go is also correct by straight area rules, but not vice versa. IMHO, that is an attractive feature.



The ⅓ pt. value is by territory scoring. By territory scoring the button is worth -½ pt.



Taking the button is not an approximation. As moha has pointed out, there are times when, if you have enough ko threats, not just to win the ko, but to delay winning the ko, you can profitably take the button instead of winning the ko. Similar positions arise earlier in the game in regular ko situations.




Don't worry. Just count area plus the button, as you are used to doing.



Right.

_________________
The Adkins Principle:
At some point, doesn't thinking have to go on?
— Winona Adkins

Visualize whirled peas.

Everything with love. Stay safe.

Potential result: players learn three different forms.

Button go may be implemented to simpilify AGA territory rules by eliminating the third pass by White. It would also make the score in nearly all cases the same as most Westerners are used to, since they play by territory rules online or in their clubs. I think they would welcome the change. Having the "first pass" lift the superko ban and not count towards ending play might meet opposition, so don't call it a pass.



That is one reason I recommend Button Go for international competition, and also for the AGA, which already uses pass stones.



The 2008 World Mind Sports Games in Beijing implemented Button Go without calling it that. They used area counting, but implemented the button in this way.

_________________
The Adkins Principle:
At some point, doesn't thinking have to go on?
— Winona Adkins

Visualize whirled peas.

Everything with love. Stay safe.

In some cases the area and territory scoring are fundamentally different. See the first diagram at http://www.harryfearnley.com/go/bestiary/msiivola/siivola.html. With territory scoring the position is seki, but with area scoring once the dame have been filled, white can start filling a big eye with no extra cost, and force balck to select which white group to capture.this leaves the other white group alive with two eyes and the adjanced black group dead.

Come to the US Go Congress this year to advertise button go. As an added benefit, we can hang out

_________________
be immersed

I think it looks even better than the original Korean text. (The diagram was quite horrible in the original version.)

_________________
Jaeup Kim
Professor in Physics, Ulsan National Institute of Science and Technology, Korea
Author of the Book "Understanding the Rules of Baduk", available at https://home.unist.ac.kr/professor/jukim/bbs/board.php?bo_table=notice&wr_id=5

Reply to a few earlier posts:

The first change to go to the button go is the adoption of the pass stone in the existing area scoring rule. (I think this is a more realistic scenario than keeping the area scoring style.) AGA already did that and.. the real question is will the Chinese rule ever do so.

Now, some people say "players do not want change", but really? I bet Korean/Japanese players who are used to the territory scoring but forced to play under the Chinese rule will absolutely welcome this change. Yes, pass stone is a little bit weird, but they already know from their experience that it is the right way to think when area scoring is in effect.

Most of all, the ability to count territory at the end of the game by themselves is really a lovely change. Now, at the end of the game, they wait for the referee to come and do the counting. It is the most uninteresting moment of the game, because they all know the result anyway.

Will Chinese player hate this change? Well, maybe some will. But I think they can accept it for the following two reasons.

1) This change does not have anything to do with the game result.

2) They are already counting the territory during the game. So why hate doing so at the end of the game?

I know some people say they prefer area scoring. As a technical scoring method, maybe. But is there a single player who actually count area after playing like.. 200 moves into the game? "Hmm.. looks like I have 188 points and my opponent has 173 points. I am now ahead by ..." No! They all count territory! "I have 82 points and my opponent has 78. After komi, I'm behind by ..." Area scoring occasionally changes the score, but they consider such changes as a side dish. "In this special seki shape, I can earn 2 more points. So, after counting territory normally, add 2 points to mine." This is what they actually do. They do not count the whole area just because it may be slight different from the territory counting.

The second change is the adoption of the rule that "the opponent of the first passer makes the lass pass." If they already accepted the pass stone, I don't think it is such an enormous barrier. (Of course Korean/Japanese players will welcome it, and the Chinese player's reaction is the only issue.)

_________________
Jaeup Kim
Professor in Physics, Ulsan National Institute of Science and Technology, Korea
Author of the Book "Understanding the Rules of Baduk", available at https://home.unist.ac.kr/professor/jukim/bbs/board.php?bo_table=notice&wr_id=5

With apologies to the late John Rickard, it is a matter of the rules. Yes, this is a standoff, and the J89 rules permit Black to pass without cost while White fills the big eye. However, as I believe Honinbo Shuwa understood, the standoff "should" be resolved when plays cost 1 point, as with capturing dead stones, when you don't let the opponent pass for free. In that case White plays first and Black replies on the board. The result is 9 pts. for White after Black makes the last play. No Pass Go with Prisoner Return indicates the same value, and it uses territory scoring.

_________________
The Adkins Principle:
At some point, doesn't thinking have to go on?
— Winona Adkins

Visualize whirled peas.

Everything with love. Stay safe.

The World Mind Sports Games rules are interesting. They implement a button (without calling it that) worth ½ pt. to White and use a 6½ pt. komi. They also use the Ing fill in method for counting the score, but can also use other methods.

_________________
The Adkins Principle:
At some point, doesn't thinking have to go on?
— Winona Adkins

Visualize whirled peas.

Everything with love. Stay safe.

Hello,
Are you talking about the adaptation of the AGA rule (with pass stones and White to make the last move) to include the button ? Then as far as I understand, Bill Spight posted the necessary modifications in page 3 of this topic.

Here are the main highlights :

• Black gives White a komi (compensation) of 6½ points [instead of 7.5]
• A special move called "taking the button," which occurs only once per game. [the button is worth nothing if we use pass stones]
• To take the button the player hands a stone over to his or her opponent as a prisoner. [but taking the button is not considered as a pass]
• After the button has been taken, it is only illegal to recreate a previous full board position with the same player to move if that position arose after the button was taken or by taking the button.
• Two consecutive passes normally signal the end of the game. The player to make the second pass does not hand over a stone if he or she also took the button.
• If the players disagree about the status of a group of stones left on the board after both have passed, play is resumed, with the opponent of the last player to pass having the move. The game is over when the players agree on the status of all groups on the board,in which case, if it is the turn of the last player to pass before resumption, that player passes and hands over a pass stone, or, failing such agreement, if both players pass twice in succession, in which case the second player to pass does not hand over a pass stone if that player played first in the resumption.

And you must add on top of all this that if some players loose their prisoners, or forget to hand over pass stones, when you have to count the game under area scoring, you must use a different komi (7 instead of 6.5), and a different value for the button (0.5 instead of 0) to re-count the same game !

I don't want to be the referee !

That rewrite is (I hope!) a clarification of the AGA rules about resumption and has nothing to do with Button Go per se. As written, this AGA rule could lead to some strange results, it seems to me.

_________________
The Adkins Principle:
At some point, doesn't thinking have to go on?
— Winona Adkins

Visualize whirled peas.

Everything with love. Stay safe.

I think that the main thing that will meet player's opposition is the fact that the button is supposed to be worth 0.5 points, but when you count the game filling territory with the prisoners, the button is actually worth zero ! It is only here to trigger a different rule about who's passing last.

I can't imagine players accepting that.

Whoa ! I have just read again the official texts of the AGA rule, the British rule and the French rule (that are both supposed to be variations of the AGA rule). And I now see large difference between their formulations.

I had never realized that the AGA and British rules demand that the status of all string are agreed before the last pass. This is not so in the French rule.
And I had never realized that they use concepts such as life and death. The French rule does not.
On the other hand, the French rule forgets to tell that the dead stones must be removed if pass stones are used to count the game !
And it also escaped to me that the French rule uses a special definition of territory.

In my opinion, the core of the rule is better in the french version. It is more or less the same as the chinese rule. The score is directly defined with the concept of area, without any reference to life or death, not even talking about removing dead stones. This allows the rule to remain clear and short.
Then, the use of pass stones, and filling territories with prisoners, is added only at the end, as an option... except that they forgot to reintroduce the part about removing dead stones there !

The part about game resumption is also unclear in the French rule. They tell nothing about what must be done.
Anyway, I think that instead of describing a list of possibilities about who passes last and who gives a pass stone, the rule should remain as short as possible :

A player may pass by handing the opponent one stone (called a pass stone) instead of playing a stone on the board. A pass is always legal. Pass stones are added to the opponent's prisoners. White must make the last move.

And there is nothing more to say. All the previous examples of who must give a stone or not are just practical applications of the above rule.

jaeup, I have described the theory for positional judgement and for endgame evaluation why, during the middle game and early to middle endgame, territory counting can be used and might be faster. However, during the late endgame under area scoring, area counting is appropriate for correct endgame evaluation, except that some theory might still allow territory counting in certain local positions or for the global stone count or result parity prediction.

Due to the equivalence in counting, popularity in analysis does not provide a justification for scoring. For some purposes of analysis, one counts stones but you would not use this as justification for stone scoring, either.