Many years ago（about 20 years), a friend sent me an email, he wants me to relinquish the copyright of the following article. I agreed.
Say hello to him, Can you receive this info?
Also, I see some people's name here, which I saw 20 years ago.

Ancient Chinese Rules And Philosophy
at: https://senseis.xmp.net/?AncientChinese ... Philosophy

_________________
Zhang-hu 章浒
Committed to the restoration Chinese traditional Weiqi
Research on ancient Weiqi rules & Classic (Dunhuang Classic and the Thirteen Chapters Classic)
From Suzhou, Jiangsu Province, China

Bill

As is often the case with me, I churn over things in my mind as I struggle to wake up, and I find my subconscious biting me in the bum. That happened today.

I had a vague notion that several people here are on different wavelengths, without being able to put my finger on it completely. I tried to convey that by stressing the context in which the phrase 角盘曲四局终乃亡 occurs, and couldn't really understand why you went off on the tangent you did. I think the penny has dropped.

I just read 角盘曲四局终乃亡 as "bent four in the corner will die at the end of the game."

However, I twigged that the problem may be that ppwq translated that as "the shape of bent 4 stones circled at the corner of the board, die at the end of the game." But there is no reference to stones in the Chinese. This is where the context matters. The context is this: An eye shape of three points in a straight line was called 直三 – Straight Three. An eye shape of three points in a line but in the extreme corner was called 　傍角直三　– Bent Three in the Corner. An eye shape of three points in triangular shape was called　曲三　– Bent three. Four empty points in a square was called　聚四 – Clump Four, but this was also used of the clumped four in a pyramid shape. Four in a straight line was calle d直四 – Straight Four. Four empty points in a zigzag shape was called 曲四. (And this last example is why bent four (points) in the corner has to be (apparently tautologically) differentiated by adding 盘.)

The ancient texts then go on to tell us the names of bigger shapes, the difference being that they start using fancy names: Cleaver Five, Tally Five, Jade Tablet Six, Flower Six, Fungus Six, and so on. The point is that these are nakade shapes for which you have to know whether they are alive or dead. And how. In the case of Rectangular Six in the corner, the ancients point out that a liberty matters, for example.

What is special about the bent four (points) shape is that in the centre of the board or on the sides of the board "it will live at the end of the game." But, freakily, bent four coiled round the corner will die (straightforward application of stone-scoring rules in all normal situations).

When we say "bent four" we think tend to think of a whole nexus of things which includes a host of things such as sekis, special rulings, liberties, the differences between Japanese, Chinese, Ing rules, etc. To the authors of the ancient Chinese it just meant a nakade shape. Occam's Razor applies. The generally simplistic views of the earliest writers are only to be expected. If they found anything unusual they can be expected to get excited about it and write about it. This happens in the Dunhuang manual with the discovery of the Rule of Six for ladders. (But they were apparently not sophisticated enough to know about ladders that go round corners - go knowledge has to accumulate.

On your point about speculating being fun - yes, but it can also be dangerous. We don't want a von Daniken in the go world. One word where I sense we may going down that route is what were called here "casino chips". These are in fact tallies made of bamboo, and have nothing to do with James Bond, of course. In one reference to them in the 13 Chapters Classic, trying to explain the text for Japanese readers, even Go Seigen added a footnote "I don't understand this very well" (よくわからない). He's not the only one to be stumped by it. But if we speculate, and stress we are speculating, there are some lines of attack that are far more reasonable than trying to impose modern rules backwards. The most obvious, because it is mentioned in the ancient texts, is handicapping. We know there was an ancient system of players of equal strength playing two games per match, with each alternating first move. Where players were of slightly disparate strength, the match could be three games. Handicaps could also change, depending on a run of results. Such handicaps and results were personal to the two players concerned and so they had to keep track of the results in an era when paper was rare and expensive. So, use tallies. Ancient emperors set up academies and grading systems and ranked players in dan grades. Just like today, this was a far more important aspect of the game to the average Zhou than arcana to do with rules.

Any problems?

the shape of bent 4 stones circled at the corner of the board,
(the opponent）die at the end of the game.

_________________
Zhang-hu 章浒
Committed to the restoration Chinese traditional Weiqi
Research on ancient Weiqi rules & Classic (Dunhuang Classic and the Thirteen Chapters Classic)
From Suzhou, Jiangsu Province, China

It is how to use "chips(筹)", guessed by Cheng en yuan(成恩元) in his writtings-《敦煌碁经笺证》.
many years ago. And it is only his guess, it's not confirmation.

We need to study more new ideas and Please don't completely deny any new ideas.

My comment:the translation of 筹 as "counting rods" is not a good translation, Now I changed it to "chips".
2020/11/19 10:23 beijing time

_________________
Zhang-hu 章浒
Committed to the restoration Chinese traditional Weiqi
Research on ancient Weiqi rules & Classic (Dunhuang Classic and the Thirteen Chapters Classic)
From Suzhou, Jiangsu Province, China

Yes, I saw that, and relied upon your translation. I also checked it with an online translation service. However, it is stones that die, and so pgwq's translation did affect me because of that. Still, I did not take Bent Four in the corner literally, either as a shape of stones or of points, because even modern references to Bent Four or nakade in Japanese do not necessarily refer to any shape that is on the board at the moment.

Click Here To Show Diagram Code

[go]$$ Bent Four in the Corner
$$ ----------------
$$ | . O . X O . O .
$$ | O X X X O . O .
$$ | . X . O O O . .
$$ | X X O O . O . .
$$ | . O O . O . . .
$$ | O O O O . . . .
$$ | . . . . . . . .[/go]

This position is called Bent Four in the Corner even though the bent four shape is not now on the board and, given the Dunhuang reference and its appearance in later texts, I would not be surprised if players at that time also called it the same. That was why I went on about how as go players we understood what Bent Four means. We know that the term is applied to precursor positions. We also say that Bent Four is dead, referring to the Black stones, which may be removed without capturing them at the end of the game.

Click Here To Show Diagram Code

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

The fact that Bent Four in the Corner is dead is why is a tsumego mistake. Something that we learned on Mother's knee. I think that the ancients understood all this and that is the reason that it appears in the Dunhuang classic. I don't think that Bent Four in the Corner meant something else to them. Which is why the term has lasted through the ages. I don't think that they regarded Bent Four as a kind of seki.



I think that's a typo, that you mean Straight Three in the Corner.



And, OC, 角. Interesting that 曲四 applied to both the zigzag and the dogleg shapes.



And I suspect, just like today, the assumption is that the nakade will be played. The Cleaver Five eye shape is not dead in itself, as the defender to play can live. But if the current position is such that the attacker could force the defender to make that shape and then play the nakade, the current position might be called a Cleaver Five.



This is helpful. It strongly suggests that Bent Four in the Corner dies like other nakade shapes die.

However, I think that the qualification, 局终, matters. When does the game end under stone scoring? There is no penalty for playing on until all dead stones are captured, or even until the board is full except for the "group tax" points. Today we do not say that the Flower Six dies (assuming that the attacker plays the nakade) or is dead at the end of the game, we simply say that it dies or is dead. And from what you say I suppose that ancient usage was the same. My point is that with stone scoring we do not need to say 局终, either. But with territory scoring we do, because the end of the game comes before we kill the group.

Chen quotes 碁有停道及兩溢者，子多為勝。from the Dunhuang Classic as indicating stone scoring, and that is a straightforward interpretation of 子多為勝. But the first part is not clear. Does it indicate that play continues until the board is full? And if so are the 子 on the board or are they in hand (prisoners)? The net score is not necessarily the same. In particular you could have a situation where the number of prisoners is the same for each side, but Black has one more stone on the board.

Chen's argument that the group tax indicates stone scoring is understandable, given recent go history. But thanks to Berlekamp in the 1980s we now know that territory scoring with a group tax is possible without being derived from stone scoring. The same is true for the no pass capture game, which is a form of territory scoring with a group tax. If ur-go was scored by prisoners, then territory scoring with a group tax could have been derived from it.

pgwq has a different interpretation of the Dunhuang Classic from that of Chen and thinks that the stones are prisoners. I look forward to hearing what he has to say.

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

Visualize whirled peas.

Everything with love. Stay safe.

Bill:

Chen's interpretation depends as much on the verb 溢 'to fill to brimming point'. I am agnostic on this, incidentally. I prefer the 'let's wait for new evidence' approach, not least because new evidence is appearing all the time. There are, for instance, now two Ming copies of the Lanke Jing that omit the extra character 死 in the bent-four phrase - in other words the version shown here has been tampered with (by a rules maven? ).

To try to give you some sense of the first part, using a trot and tag translations:

者 is a topic particle like Japanese は (as for, as regards, when, etc). The topic is the whole of 碁有停道及兩溢.

碁 'go' you know, though do note it's the old for labelled (incorrectly) as Japanese, and of course as in Japanese it can mean 'the game'.

有 'has' you know.

停 is a bit trickier. Its basic meaning (the one given in the ancient Shuo Wen dictionary) is 'to stop'. Various other related meanings have evolved (and bear in mind the Dunhuang manual is several centuries later). One that may or may not be relevant is 'to settle'.

道 is what 停 is stopping. Note that carefully. 道 means 'road'. In Chinese go it referred to the lines on the board, i.e. empty, exposed lines. By extension it can mean (unoccupied) point. This is not much different from English where we can refer to the size of a go board as '19x19 lines' or '19x19 points, it all being a matter of the perspective you start with. And of course was it not Euclid who hypothesise that a line is a row of points？

及 'and' you know

兩 'two' but used for 'both sides'

溢 'fill in to the overflow point'.
Chinese is fundamentally an S V O language like English, but you have to supply tenses and plurals yourself. So, using artificial English and adding back the topic marker, we can posit a meaning such as 'after the game has a stopping of [play] on empty points and [then] both sides have filled in, [the one with more stones becomes the winner].

However, the Dunhuang text continues: 取局子停，受饶先下者输。纵有多子，理不合计。 In other words, it gets very murky. E.g. How did handicaps cone into this? It goes on even more than that by referring then to "cannon go" (or the cannon game") which may well refer to what has been called "pellet chess" in English. This is a kind of caroms which was extraordinarily popular in both China and Japan. It inspired essays, some of which have been misinterpreted as go manuals, and led to much confusion. There are also grounds for believing that some of the specific terminology defined in the old go manuals derives from other games such as pellet chess or liubo. The problem is we don't really understand these terms in the context of their original games, either (although liubo may have been 'solved' recently - I only keep half an eye on this field nowadays).


To go back to 停, though: in the Miscellaneous Chapter 13 of the eponymous classic, talking about tallies 籌, we see a different usage. Note that in this classic, 路 also meanings 'road', now replaces 道 but is used in the same ambiguous way (lines/intersection=points). The text says "Winning having more 路 is called 赢 [winning, but possibly an obscure term borrowed from another game]. Losing by lacking 路 is called 输籌 [losing a tally]."

There is a suspicion that the word tally is missing after 赢.

The text then goes on: 皆籌为溢。 Prof. Paolo Zanon translated this as "When both players have won one game each they are equal" which in my view is tantamount to saying he doesn't know what it means. I certainly don't. The next phrase is an apparent non sequitur: 停路为芇. Zanon gives "A game is declared a draw when both players have acquired the same number of intersections." Let's just call this a bold interpretation. The only thing we really confident about is that 芇 means a draw or jigo.

But, ***speculating***, imagine a clerical error and a simple transposition: 皆籌为溢 >> 皆籌为芇 >> and 停路为芇 >> 停路为溢. That way we would restore parity with the Dunhuang phrase (except for using 路 for the synonym 道), and more importantly it would make sense: "Equal tallies is a tie. We stop [playing] on the intersections and fill in." That doesn't address the non sequitur, although to a degree you can do that by adding punctuation (i.e. insert a paragraph marker between those two sentences).

The very next phrase incidentally is 打籌 (which is the term Go Seigen didn't have a clue about) 不得过三 and then (assuming punctuation here) 淘子不限其数。 Zanon plunges in where GSG hesitates and translates the first bit as "Matches should not be composed of more than three games each." For the second half he gives "When you count your pieces do not worry about how many you have won." GSG avoids the issues and just says that the 淘子 are not limited in number.

淘 means basically to wash (hence the water radical) but came by stages to mean to dredge and then to scoop and then to remove. It will no doubt excite researchers looking for prisoners, and may even mean that. But by saying the number of prisoners is unlimited we are not really saying they exist. It may mean that we don't count them so there's no need to know the exact number. At a pinch it may refer to the process hypothesised as the transition between stone counting and territory counting in which some parts of the board can be filled in with stones but parts can also be "scooped out" so that you count stones + territory. But do note that all this speculation relates only to the 13th century text, when territory counting was definitely in force in China. It does not relate to the Dunhuang text.

As you will infer, I have no definite views on the meaning of either of these texts. I have merely tried to show some of the problems that are involved: an extreme paucity of material, corrupt texts, possible anachronisms, ambiguities. I personally prefer to await more material. But if you do choose to speculate in depth I think two cautions apply: (1) establish why and for whom the text was originally written - it is hardly likely to have been for rules mavens; (2) do not impose modern mindsets on the ancient texts - in other words, do not make the facts fit the theory.

talk nonsense

_________________
Zhang-hu 章浒
Committed to the restoration Chinese traditional Weiqi
Research on ancient Weiqi rules & Classic (Dunhuang Classic and the Thirteen Chapters Classic)
From Suzhou, Jiangsu Province, China

Thank you very much for your detailed exegesis, John. It is very informative and helpful.

Let me start at the back end. Maybe more later.



I do not wish to speculate in depth. I do wonder if there was an earlier form of go with the object of capturing stones. That is similar to pgwq's interpretation of the Dunhuang Classic, so I am interested in seeing what he has to say.

I do agree that it was not written for rules mavens or lawyers. More on that a bit later. And, OC, distorting facts to fit a theory is not good.

However, interpretation is impossible without theory. That's why there is an agreement that parsimony is desirable. I.e., it is good to have a parsimonious theory of interpretation. Occam's Razor was originally about keeping the number of entities posited by your theory to a minimum. That does not exactly apply to textual interpretation, but minimum description length (MDL) does. Now, MDL applies only given a descriptive language. So what descriptive language do you use? That's an open question, last time I looked.

I think that you and I both agree that context is important. One point where we seem to differ is that I consider the statement about Bent Four in the Corner to be important context, while you do not, because it is not in a section about rules. I don't that matters much, precisely because the Dunhuang Classic was not written for rules mavens. To say that Bent Four in the Corner is dead (or dies) at the end of the game tells us something about how the game was played. The 1949 Nihon Kiin rules included it in the rules, but other modern rules do not, conspicuously area scoring rules. Area rules do not need it.

For how theory affects interpretation, we need look no further than Chen's The History of Go Rules (2011). In the second sentence he says, "we all know that territory scoring has logical flaws", That is a modern theory that has been thoroughly debunked. Not to defend the Nihon Kiin rules, but the territory rules of Berlekamp, Lasker-Maas, myself, Ikeda, and, I suppose, Shimada, as he was a mathematician, are all logically impeccable. There are a number of places where that theory seems to affect Chen's interpretations.

The Dunhuang Classic states: 碁有停道及兩溢者，子多為勝。OC, on its face it indicates that the player with more stones wins. Fair enough. But how does Chen interpret 停道 (stop road). He states:

I'm sure he is right, that that is a possible interpretation, but it hardly seems definitive. And it fits with the idea that there is something wrong with counting territory. If the territories are equal, then you can ignore them. But to assure that they are equal, you have to count them. Did stone counting in the modern era depend on equalizing territory? Surely not. This interpretation does not seem parsimonious, but it fits with the modern theory of the illogicality of territory scoring.

Chen continues:

Now, this is a way of doing area scoring. It's one of the AGA methods of counting the area score. So far, so good. But does C&IP actually mention that method?

Chen goes on to quote the C&IP:

There is a bit of a snag there. Can the play of equal stones be taken for granted? Chen examined the four relevant game records in the C&IP and found that, indeed, there was an expectation of an equal number of plays by each player. In addition, as with stone scoring, the scores do not fit the raw territory scores, but they do if there was a group tax. So far the reported scores do seem to be a method of calculating the score by stone scoring. However, play ended with dame left unfilled. For equal plays to guarantee the same result as stone scoring all the dame must be filled. Chen missed that implication.

Chen's conclusions include these:

(Emphasis mine.)

This is a reasonable conclusion as far as it goes, as a group tax with territory scoring does not seem to be justified. Berlekamp's rules were only published in one book in 1994, Mathematical Go, with an English and a Japanese edition. Berlekamp's territory rules naturally have a group tax. In fact, he went to some effort to eliminate the group tax in a variation of the rules.



An incredible oversight! Chen saw that when the dame are not played out it does not matter who plays the last stone (move). But if it does not matter who plays the last stone, you don't have stone scoring. He failed to draw that conclusion.

Example:

Click Here To Show Diagram Code

[go]$$B Dame unfilled
$$ -----------
$$ | . O X X . |
$$ | . O O X . |
$$ | . O . X . |
$$ | . O X X . |
$$ | . O O X . |
$$ -----------[/go]

Equal plays by each side, one dame unfilled, net territory score = 0.

Click Here To Show Diagram Code

[go]$$B Dame filled
$$ -----------
$$ | . O X X . |
$$ | . O O X . |
$$ | O O X X . |
$$ | . O X X . |
$$ | . O O X . |
$$ -----------[/go]

Equal plays by each side, dame filled, net stone score = 1 point for Black. You can use territory counting to get the net stone scoring result, but only because the dame have been filled.

It is hard not to suspect that Chen had a mental block based upon his low regard for territory scoring.

Edit: Actually, Chen does notice that the result of Jia Xuan's Game is an 8 point win for Black, while the correct stone scoring result would be a 9 point win. His conclusion? Not that the players were actually playing by territory scoring, but that they were doing it wrong.

(Emphasis mine.) Territory counting, not 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.

Bill

To pick up on a couple of issues in your last post and to add a little I forgot to include earlier.

First, your remark about a discrepancy of point being a stumbling block in Chen's theory. I have no idea what he personally feels about that, but I do remember someone (can't remember who, when or where though I have a vague recollection is was in connection with Qing games and stone scoring) arguing that the ancients wouldn't worry about a mere point that would rarely affect the result when they were already allowing first mover (White) a much bigger advantage. But in any event, they apparently did take account of both points by not treating a contest as a single game. Even handicap was therefore two games, alternating colours. There were also contests of three games, and these were known at least in the 13 Chapters Classic: the Miscellaneous Chapter 13 being discussed here has the sentence: 棊有敌手有半先有两先. I have already said I feel uneasy in general about applying modern assumptions to old texts and practices, and I think this is an easily understood example of why it can be dangerous. Modern thinking is used to the notion that a single game matters and must have a clear result, because we have so many knockouts and other single game encounters. Things were more leisurely in the olden days and so they didn't need to think that way.

Second a couple of things I forgot. These are just me continuing to show why caution is always needed.

One was to talk about the character 芇. Nowadays this is taken to mean jigo in go. But its first occurrence in a go text appears to be in the commentary on Chapter 13 - or what is regarded as the commentary - there is some debate about this. The C&IP in Chinese is the Wangyou Qingle Ji, which takes its name from a poem by the current emperor and was published apparently in 1119, by which time Liu Zhongfu (the Meijin of his day) was dead. The C&IP itself has been dated to 1150 by Chen Zuyuan, but it refers to Liu twice, and in one case it refers to him is a man of "today". Wangyou Qingle Ji as a book name, however, appears to have been devised by Huang Pilie, a famous collector of relatively recent times who is the person responsible for us having the sole surviving copy which is now in the China National Rare Books Library.

However, two things should be noted about this book. One is that it has at some stage been rebound and the pages have clearly not been put back together in the right order. The other is that it is not necessarily (and probably is not) the original version of the book. It appears there was another, earlier book called Wangyou Ji and this was attributed to Liu Zhongfu. What we now know as Wangyou Qingle Ji is therefore assumed to be re-edited version of that earlier book (perhaps the emperor took his inspiration from Liu Zhongfu's title?). But this means, in short, that we can't be sure exactly what was in Liu's original book.

Another point I forgot to make when talking about 停路 is that this term evidently gave even the ancients some trouble. It is mentioned in Zhang Jing's text in form 停路为芇. The commentary then tells us that 芇 is pronounced like 绵 and that it means 相当，it refers to the case where neither side wins nor loses. And finally it tells us that 停路 was a "popular" term for 芇.

Without in any way saying that is wrong, that commentary evokes in me a couple of reactions. One is that the original writer evidently felt 停路 needed explaining (停路为芇). The fact the commentator mentions it was a popular term （芇俗云停路） is not necessarily a problem. He uses the word 云 which tends to be used of citations from the past. Another reaction is that it is almost as if the commentator had to go and look up the word 芇. he had to give its pronunciation (mian) for one thing. For another the definition just happens to be the one (as he himself says) in the Shuo Wen dictionary: 相当 (to match, correspond to, be equivalent to, be equal to). However, he could also have consulted the 广韵 dictionary which was compiled in 1008, and so was in the same time frame, and that tells us about 芇 that 今人赌物相折谓之芇 (modern people when they gamble and lose call this 芇). Although this meaning is ignored by people like the commentator and moderns like Chen Zuyuan, and we always have to bow to the native speakers, it seems worth noting it is game-related and ancient go was a hotbed of gambling. And it is also worth noting that another natuve speaker seems to take a different view. Go Seigen renders this knotty phrase 停路 as 停局 in Japanese, which we would expect to mean (even in Chinese) as 'stopping the game'.

To diverge from textual exegesis entirely, I read an announcement this week that the famous Shosoin boards will be on display again soon (they usually show them for about a week once every 20 years). There is a general assumption, I believe, that these boards were made in Tang times in China (though perhaps by Korean craftsmen) and this was the time when Japan was introduced to go by China (though the modern view seems to be shifting to a much earlier date) and that China was then using territory rules. I think one of these boards confirms that.

I seem to be the only person to have pointed this out (judging by the reaction at a symposium in Korea where these boards were discussed), but the most famous board has two small drawers embedded in the board. When you pull one, the other opens on the opposite side. Then assumption then was that these were for storing the pieces. But I had recently seen the boards for myself in Nara and could point out that the drawers seemed nowhere like big enough to hold all the pieces, besides which the collection also includes nice bowls. The only sensible use I could see for these drawers is to hold prisoners.

Whether that's true or not, one apparently unshakeable piece of evidence for territory counting in Tang times is the famous Makibi no Kibi story. But that story is in fact quite shakeable, as I have demonstrated in (I think) Go Companion. It's almost unilaterally a Japanese story with no back-up in China, and the various elements can be shown to have accrued incrementally over a long period in Japan.

But if we do persist in sticking to Tang = territory, it seems to me that no-one has tried to account for how that squares with the Dunhuang manual. Of course the text precedes the Tang, but the manual we have today is dated to the 9th century, it apparently being a monk's handwritten copy of a selection of his favourite bits of go knowledge and wisdom. If he was describing stone-counting rules in an era when, by one theory, territory counting was in force, surely he should have either omitted that bit or made some comment on it.

I'm sure it must feel as if I've given a veritable tsunami of points just to illustrate my (strong) view that the whole business is mired in mirk. If illumination is sought, my instinct is to insist on squaring the linguistic evidence, and archaeological evidence if there is any. In other words to use the evidence of the past and not modern assumptions. Nevertheless, I concede there is room for other prisms, and that brings me to a question where the rules-maven approach is probably more insightful.

If we assume China did in fact start out with territory rules (and with group tax being feasible as Berlekamp has discovered), what would the change to stone counting have meant in practice when it occurred in the late Ming. My feeling (which seems confirmed by the many plaintive queries we see and hear every day in our modern go world) is that the changeover would have been a massive undertaking, and would have evoked Brexit-like divisions of opinion. Yet the page is turned with no comment! So, why make the change (problems with missing or stolen prisoners seems like a feeble excuse to me) and why is there no major upheaval?

The best scenario I can come up with is that perhaps the two systems had been concurrent for centuries - stone counting in the north (where the Dunhuang manual comes from) and territory counting in the Tang capital Changan and the south. Under that speculation, we can say that the Qing came from the north and with the status and power of conquerors imposed their version of go almost by fiat (pockets of the Ming dynasty retained power in the south as local warlords for some time, which is why timelines can sound messy).

So, Bill, what's your view of that changeover?

I like your hypothesis. Every popular game I know of has local rules. Usually they are not written, and if you are a visitor you find out about them when you violate one. If anything, what is remarkable about stone scoring and territory scoring with a group tax is their standardization. And the difference in final scores, which is only ½ point on average, matters in only a tiny fraction of games. There is not much to choose between the two.

Today, the modern idea of the pass has been adopted across the go world. Games end by passes. But traditionally games ended by agreement. One aspect of the Takahashi-Segoe dispute was that Takahashi refused either to make a play once the dame had been filled or to agree to end the game.

The lack of passes gives an explanation for the group tax. Who is going to make a play that puts his own living group into atari? OC, if you are simply placing stones on the board after the play is over in order to score the game, that does not matter.

But even on a 17x17 board, who wants to take turns playing inside your own territory? In practice, play stopped well before that point and the players scored the game as though they had played it out to the bitter end. But if there was no history of playing the game out, how did the idea arise in the first place?

The Dunhuang Classic, at least the parts that I know about, does indicate or suggest that games were played out to the bitter end, and that stone scoring was used. There is no mention of the group tax. IMO, Chen busts a gut to try to find it in the text. But that is hardly necessary. What player is going to kill his own group?

Still, even if the object of the game is to put living stones on the board, why play the game out as a general practice? A natural place to stop play and score the game is when the last dame is filled, instead of playing on for possibly more than 100 moves.

Here is my speculation. What if the object of the game were to capture the opponent's stones? Then of course you would play to the end, at least until one player would be forced to play inside the opponent's territory or kill his own group. At that point you could even count the opponent's territory with a group tax to determine the score. OC, we have neither game records nor text to indicate that such a variation ever existed. But it has a group tax and counts stones, like stone scoring, while its score is the same as that of territory scoring at the point that play stops. Such a game could have been the ancestor of both forms of scoring.

In any event, variants of widespread popular games are almost sure to exist at any time. I think that coexistence is the most likely hypothesis.

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

Visualize whirled peas.

Everything with love. Stay safe.

After amendement of many times, part 2 is ok now.
part 2: ancient rules in texts & annotations of 13 Chapters Classic at https://www.lifein19x19.com/viewtopic.php?f=45&t=17866

Now,writting part 3.

_________________
Zhang-hu 章浒
Committed to the restoration Chinese traditional Weiqi
Research on ancient Weiqi rules & Classic (Dunhuang Classic and the Thirteen Chapters Classic)
From Suzhou, Jiangsu Province, China

"Group tax" is the "tax" for group alive forever on the board.
and the simply pass is not good inventation.

At the times of Dunhuang, after "both parties overflow"("两溢"), the game is end.
Both parties overflow is pass & hand over prisoner eachother.

Many people are too deep into the Japanese go rules Or the so-called modern go rules, including many Chinese.

_________________
Zhang-hu 章浒
Committed to the restoration Chinese traditional Weiqi
Research on ancient Weiqi rules & Classic (Dunhuang Classic and the Thirteen Chapters Classic)
From Suzhou, Jiangsu Province, China

Well, pass is a modern idea in go rules. And I proposed passing and handing over a stone to the opponent in 1977. Nobody responded, yeah, yeah, we know.

Edit: Ing rules defined pass as a kind of move in the 1970s. In 1932 Yasunaga's rules (constitution) proposed ending the game with 3 passes, referred to as giving up the right to make a play: 終局、交互着手の権利を連続３回放棄せる場合。Is there anything earlier?

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

Visualize whirled peas.

Everything with love. Stay safe.

Because it will let group tax back to Japanese go rules, and which was tampered with by Japanese.

Some Chinese are trying to restore the traditional Weiqi rules, including me.

_________________
Zhang-hu 章浒
Committed to the restoration Chinese traditional Weiqi
Research on ancient Weiqi rules & Classic (Dunhuang Classic and the Thirteen Chapters Classic)
From Suzhou, Jiangsu Province, China

I suppose you are aware of No Pass Go with Prisoner Return? See https://senseis.xmp.net/?PrisonerReturn

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

Visualize whirled peas.

Everything with love. Stay safe.

In fact, in the times of Dunhuang Classic and Song Dynasty, people were avoiding the last dame profit problem.
Why do they try to avoid this problem? Because they've met.

_________________
Zhang-hu 章浒
Committed to the restoration Chinese traditional Weiqi
Research on ancient Weiqi rules & Classic (Dunhuang Classic and the Thirteen Chapters Classic)
From Suzhou, Jiangsu Province, China

Prisoner return should be equivalent to handing over own piece.
But I don't know. I only know some of ancient Weiqi rules.

_________________
Zhang-hu 章浒
Committed to the restoration Chinese traditional Weiqi
Research on ancient Weiqi rules & Classic (Dunhuang Classic and the Thirteen Chapters Classic)
From Suzhou, Jiangsu Province, China

With prisoner return you do not need a rule to end play by consecutive passes. With consecutive prisoner return somebody will run out of prisoners to return.

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

Visualize whirled peas.

Everything with love. Stay safe.

First,both parties get maximum number of prisoners, <<<<< similar as "both parties overflow(两溢)" of Dunhuang Classic
then, return prisoners, finally see who still has prisoners? <<<< similar as Net Score of prisoners of Dunhuang Classic

Is my analysis correct?

_________________
Zhang-hu 章浒
Committed to the restoration Chinese traditional Weiqi
Research on ancient Weiqi rules & Classic (Dunhuang Classic and the Thirteen Chapters Classic)
From Suzhou, Jiangsu Province, China

I don't understand the Dunhuang Classic well enough to say.

But the only way to get a prisoner in No Pass Go with Prisoner Return is to capture one.

Edit: And as a human, instead of returning a prisoner, if you have one, you should probably suggest stopping play, since returning a prisoner costs you one point.

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

Visualize whirled peas.

Everything with love. Stay safe.