Strategic differences due to group tax

[Bill Spight]

Has capture / no-pass (= obligatory move, not simple lack of passes) rules ever appeared in practice before recently?

... the illogical ruling that White (Segoe) won but Black (Takahashi) did not lose. But the Japanese did not know whether a move was obligatory or not.

These are what I meant by simple lack of passes, in these cases nobody claimed that to keep moving until no more legal moves exist (inside territory) would be obligatory.

My understanding is that the question was debated at that time. It was not just that Takahashi refused to capture the ko stone and fill the ko, as the referee, Iwasa Kei, directed him to do. The Igo Club web page I linked to on the SL page has disappeared, and I have no access to the writings at that time.

What virtual moves? I know of no text that talks of virtual moves.

The sensei's page for stone scoring etc mention them, but it's unclear how much credibility is behind. I MAY have come across this one other source as well, but don't remember where.

But a last ko with no dame and no threats is something that likely came up somewhere in history, so one could at least expect a hint from some old sources?

OC, 10,000 year kos are not that uncommon. The practice if the ko was not fought to the end was as Iwasa said, for the player who could safely take and fill the ko to do so at the end of play. There were no written rules.

If an unfilled ko remained after all the dame were filled, there was no agreement about what to do. As I understand it, both Shusai and Go Seigen favored leaving the ko unfilled and counting the empty point as territory. Kubomatsu, who was Takahashi's team captain, disagreed, and thought that the ko should be filled. The disagreement between Kubomatsu and Shusai may have played a role in the politics of the Segoe-Takahashi dispute. It may have kept the Nihon Kiin from approving a written set of rules until after Shusai died. In those rules making a play was considered a right, not an obligation. Except, OC, the obligation to fill a ko at the end of play.

[jann]

in these cases nobody claimed that to keep moving until no more legal moves exist (inside territory) would be obligatory.

My understanding is that the question was debated at that time. It was not just that Takahashi refused to capture the ko stone and fill the ko, as the referee, Iwasa Kei, directed him to do.

Well, an actual pro game where they keep filling up territory, even the last eyes, allowing the opponent to capture does feel like a strange idea to me.

OC, 10,000 year kos are not that uncommon. The practice if the ko was not fought to the end was as Iwasa said, for the player who could safely take and fill the ko to do so at the end of play.

So, what does the other player do (no dame) between opponent taking and filling the ko?

[John Fairbairn]

My understanding is that the question was debated at that time. It was not just that Takahashi refused to capture the ko stone and fill the ko, as the referee, Iwasa Kei, directed him to do.

According to Iwasa's own account in Kido 1929-01 (i.e. very shortly after the game) there is no indication that he made a ruling. He did say he had expected Takahashi to connect and that he was surprised when they went on playing dame. But as the game was not agreed to be finished he evidently did not make a ruling. He may have done so eventually (and we can probably safely infer what he might have then said) but he was left betwattled by Kubomatsu who came over and claimed it was a void game.

Both players maintained their different viewpoints, which were published in the Oteai Bulletin immediately after the game. There was no talk of passes or obligation to play or other modern constructs. Segoe based his claim on custom. Takahashi relied more on a gut feeling that it was illogical.

Baron Okura made an administrative ruling, not a go ruling. He was fed up with petty squabbles among players. And it wasn't just East-West politics, incidentally. Segoe and Shusai didn't get on, and Takahashi was the younger brother of Shusai's wife.

But Segoe didn't let it go. In the 1930-01 issue of Kido he presented a long article which he said was based on logical thought rather than trying to warm up cold ashes. I translated this in 2016 and have a note in my file that is headed: "Translation (copyright 2016) by John Fairbairn. Public use allowed only on the L19 go forum." That suggest to me that I may have posted it here already, if someone wants to try and find it.

If it's not here, I'm not going to post it now because there will be too much work creating diagrams, but the following introduction will indicate what Segoe's claimed intentions were.

After last autumn’s problem arose, I tried giving some thought to various situations, and it was rather interesting. It may even be possible to create some sort of “constitution” [a pun on his name]for this but I just tried visualising actual scenarios. I am not venturing an attempt at special pleading on my own behalf. This is a disinterested opinion.
In go it is not possible to infer anything about the whole game on the basis of just one part of the board. The outcome of a problem in a corner of the board may be determined by the size of ko threats, and if neither side has any ko threats, a ten-thousand-year ko simply has to be regarded as seki.

He backed this up be demonstrating positions with double ko sekis, so he was at that stage not arguing about this particular game directly, but rather was trying to turn it into something theoretical. As with all logic, the destination depends where you start from, and his starting point included the assumption that a triple ko was a void game. He made no mention, thohgh, of passes or obligations.

As a practising pro, he was also mindful of real life:

In other words, if White gives up the lower right corner, he loses by 3 points, but if he allows the seki in the lower left to break it is jigo. Because this is a problem of counting, which you can solve by calm reflection, although it is very easy to go astray as it involves giving up something large to rescue something small.

Hw as also a man of often strong opinions. They included this one:

Filling in dame one by one is the height of stupidity.

That's one reason he's one of my favourites!

[Bill Spight]

in these cases nobody claimed that to keep moving until no more legal moves exist (inside territory) would be obligatory.

My understanding is that the question was debated at that time. It was not just that Takahashi refused to capture the ko stone and fill the ko, as the referee, Iwasa Kei, directed him to do.

Well, an actual pro game where they keep filling up territory, even the last eyes, allowing the opponent to capture does feel like a strange idea to me.

Well, apparently, as John Fairbairn indicates below, Iwasa did not tell Takahashi to do that after the dame had been filled, or at any time. The statement on the SL page that he did so, and then Kubomatsu said there was a problem came from the linked Igo Club page which no longer exists. But certainly nobody suggested at that time or later that the players fill in territory. The players, according to the Igo Club page, did fill in the dame, while Takahashi avoided taking and filling the ko.

OC, 10,000 year kos are not that uncommon. The practice if the ko was not fought to the end was as Iwasa said, for the player who could safely take and fill the ko to do so at the end of play.

So, what does the other player do (no dame) between opponent taking and filling the ko?

That's not what I meant. The Japanese practice was to leave the dame unfilled. The opponent could have filled a dame between the taking and filling of the ko, or it could have happened informally, just as making protective plays was. IMX, as the dame were being filled without alternating play, if your opponent needed to make a protective play, you pointed that out.

[Bill Spight]

My understanding is that the question was debated at that time. It was not just that Takahashi refused to capture the ko stone and fill the ko, as the referee, Iwasa Kei, directed him to do.

According to Iwasa's own account in Kido 1929-01 (i.e. very shortly after the game) there is no indication that he made a ruling.

The statement that he told Takahashi to do so came from the Igo Club page, which no longer exists. {shrug} Doing so does not necessarily mean that he made a ruling. As a bridge TD, where irregularities happen all the time, I know that you may make a friendly suggestion without making a formal ruling. If Takahashi had taken and filled the ko, Iwasa would not have had to make a ruling.

He did say he had expected Takahashi to connect and that he was surprised when they went on playing dame. But as the game was not agreed to be finished he evidently did not make a ruling. He may have done so eventually (and we can probably safely infer what he might have then said) but he was left betwattled by Kubomatsu who came over and claimed it was a void game.

Both players maintained their different viewpoints, which were published in the Oteai Bulletin immediately after the game. There was no talk of passes or obligation to play or other modern constructs. Segoe based his claim on custom. Takahashi relied more on a gut feeling that it was illogical.

That the question of whether a play was a right or obligation came from the now nonexistent Igo Club page. But even if it did exist, it would be only a secondary source, unlike the Oteai Bulletin or Kido. As I recall, Yasunaga's proposed rules (Constitution) of 1932 (4 years after the Segoe-Takahashi incident) referred to relinquishing the right to make a play, which we now call passing.

But Segoe didn't let it go. In the 1930-01 issue of Kido he presented a long article which he said was based on logical thought rather than trying to warm up cold ashes. I translated this in 2016 and have a note in my file that is headed: "Translation (copyright 2016) by John Fairbairn. Public use allowed only on the L19 go forum." That suggest to me that I may have posted it here already, if someone wants to try and find it.

I only found something from 2013, here https://www.lifein19x19.com/viewtopic.php?f=10&t=7613 . which also talks about a game in 1943 where a pass did occur.

{Segoe} was also a man of often strong opinions. They included this one:

Filling in dame one by one is the height of stupidity.

That's one reason he's one of my favourites!

He was hardly alone in holding that opinion. It was virtually universal among Japanese players at that time. Even the Japanese 1989 rules, which appear to force the filling of dame during play, because of the new definition of seki, apparently did allow the dame to be filled informally, and the practice continued. But since then the failure to make a protective play during the dame filling stage has caused a flap.

[John Fairbairn]

I only found something from 2013, here https://www.lifein19x19.com/viewtopic.php?f=10&t=7613 . which also talks about a game in 1943 where a pass did occur.

That's not it.

The 1943 game is GoGoD 1943-05-26c. See also my book "The Incident Room" (which also has Iwasa's own actual comments). This too related to uncertainty over a 10,000-year ko.

As I recall, Yasunaga's proposed rules (Constitution) of 1932 (4 years after the Segoe-Takahashi incident) referred to relinquishing the right to make a play, which we now call passing.

Yes, though his first draft was as early as 1929, in connection with the above game. The constitution is given in New In Go 54, where you can also find Shimada Takuji's Primitive Rules of 1934. This marked the time when mathematicians first got seriously involved with rules. A fell day!

[RobertJasiek]

We do not know whether there were Chinese rules mathematicians centuries ago. IIRC, Olmsted (USA) started with it during the early 1920s, i.e., before the Japanese, who learned from him and Robinson.

[John Fairbairn]

IIRC, Olmsted (USA) started with it during the early 1920s, i.e., before the Japanese, who learned from him and Robinson.

I see I transposed two digits: Shimada's book was 1943 not 1934. Sorry. And in that case he may have been inspired by Olmsted and Robinson, whose book Rationalisation of Go was (I think) published in 1941. But would a Japanese in 1943 get to see that? However, according to Hayashi Yutaka, Olmsted started by making contact with Yasunaga and with Nogami Sho, and I believe they pointed him at the workd of Fukuzawa Sanpachi who did write about go and who produced several mathematical treatises in, at least the very early 20th century.

We do not know whether there were Chinese rules mathematicians centuries ago.

Precisely. So that's irrelevant. But we do know that the go board stimulated Chinese mathematicians. Like many people still today, they were intrigued by the possible number of positions.

Yi Xing (672~717) is the first known to us. He was a Buddhist monk who specialisied in mathematics and astronomy. He made great contributions to the then important science of calendars. His go work is lost but Shen Kuo (1030~1093) mentions it in the Mengxi Bitan (Dream Pool Essays), which was published in 1086. Under the title "A problem of the mathematician Yi Xing", he quotes and discusses an early attempt at calculating permutations.

Given that Shen had an advanced interest in engineering, medicine, astronomy and cartography (and as a Chancellor of the Hanlin Academy had access to all the best sources), and that his Dream Pool Essays was an encyclopaedic collection of notes on most of the then known sciences, I think it is reasonably safe to assume he would have mentioned any other major work on go mathematics.

Around the time of World War I, Italian scholar G. Vacca pointed out an apparent error in the permutation method, and Needham has also discussed this. But as far as I know these westerners were probably not aware that the number of legal positions postulated by Yi Xing might depend on the Chinese rules then in force. There's a project for you!

[Bill Spight]

BTW, let me emphasize that playing a no pass game does not necessarily mean that play continues to the bitter end. No pass games typically reach a point where the next play is costly. At that point play can stop and the game can be scored. For go that point is when the last neutral point has been played. Players are not required to fill in territory. They can count it.



Here is an sgf file for filling the final dame of the Segoe-Takahashi game. At that point, under no pass go with prisoner return, the 10,000 year ko has a local score of 3 pts. for Black, 1 pt. for taking the ko, 1 pt. for filling the ko, and 1 pt. for returning the captured White stone. These plays would not actually have to be made to score the game.

And a simple unfilled ko when the dame have been filled would count as 1 pt. of territory, in line with the opinions of Shusai and Go Seigen for regular go.

With no ko threats, Three Points without Capturing would be scored as such, and simple Bent Four in the Corner would be dead.

[avo]

Do any of these authors mention Button Go? It is a way of unifying area and territory scoring that has already been used in international competition (although not by that name).

I'm sorry but I'm not interested enough in rules to go and look again. I have seen it and/or other western ideas (??Maas, ??Lasker-Maas) mentioned in some places (magazines), though I can't remember your name (or Robert's) being mentioned. Chen knows about these things, of course, but I never bothered to ask him what he thought of them. I wouldn't have understood the significance of his answer anyway.

I remember Robert's name being mentioned several times in one of Chen's online articles I have once read at some point.