So I was just wondering what people thought of these names. I imagine all readers know what a ko is, most probably know what superko is. However, can you actually tell these 3 flavours of ko apart, without referring to their definition?

I've always considered these names to be pretty non intuitive myself. If they were renamed, it would surprise me if the same three names were chosen.

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North Lecale

Well, it helps to know what position and situation mean. Superko refers to the whole board, of course.

Position: a configuration of stones.

Situation: a position plus whose turn it is.

So a positional superko is one that repeats a whole board position. A situational superko is one that repeats a whole board situation.

As for natural, that is PR, isn't it?

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

Visualize whirled peas.

Everything with love. Stay safe.

Positional superko and situational superko seem like fine descriptive names to me, as Bill has explained. The meaning of natural situational superko is not apparent from its name. Perhaps a name like Causative Superko or Causative Situational Superko would have been better?

If you look up the definitions, you'll probably see the distinction is quite blurred, certainly from the point of view of common usage. For example http://dictionary.reference.com/browse/position

edit, that super acts to dictate whole board consideration is not obvious from most definitions I have read, or certainly, not as obviously defined as it should be.

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North Lecale

This is very helpful to know. However, let me stir the pot a bit.

Situation: a configuration of stones.
Position: a situation plus whose turn it is.

We are talking go terminology, you know. "Position" was used to mean a configuration of stones long before the term was adapted to distinguish a kind of superko. The first use of the term, "superko", to the best of my knowledge, was in the English version of the first Ing rules in 1974 or 1975, and referred to positional superkos. "Territory" and "area" are synonyms in ordinary English, but have different meanings in go. "Territory" was established first, just as "position" was. A non-go dictionary is unlikely to tell you about go usage.

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

Visualize whirled peas.

Everything with love. Stay safe.

Richard Nixon told Petrus that he had forgotten his name. It was the first time he didn't lie.

Superko is a well established term and quite practical instead of "rule of prohibition of whole board repetition". Position is a well established term. IIRC, in about early 1997 Matti Siivola suggested to the go-rules mailing list the use of situation. Since then, very quickly rules freaks have adopted that, applied it to superko and (among expert talk) used the abbreviations PSK and SSK. In 1997 I rediscovered (Terry Benson claims to have meant NSK for AGA1991 but everybody else reads SSK into the text) and named natural situational superko, abbreviation NSK. (There are also other superko variants incl. Robinson-Olmsted superko and Spight superko but we do not need to discuss them in this thread for the sake of PSK, SSK, NSK nomenclature.)

Since now superko, position, situation (as its rules term derived meaning; there is also a different informal meaning) are well established terms, non-immediate understanding of the phrases "positional superko" and "situational superko" is the reader's fault of insufficient knowledge of acknowledged terminology. This leaves only the "natural" of NSK to be discussed.

1997 was a hot rules freaks year with new discoveries every second day or so. Rather than spending days on reflecting how appropriate a new name was, one would rather go for the next research. So in the heat the battle, I came up with "natural".

Both SSK and NSK are variants of situation-dependent superko. So in an ideal world, both should have a name like "variant-x situational superko".



It was about 1/3 PR and 2/3 attempt of contents reflection based on the following observation:

* SSK: The causes for later ko bans are created by [board] plays or passes. The later application is only for plays.

* NSK: Both the cause for later ko bans and the later application are related to plays.

This identity of cause and application is the "natural" aspect of NSK. SSK misses this identity and I call that "unnatural".

With a single other word, one would also not please our intuition. It requires at least about a whole sentence to explain the difference. So I doubt that any other modifier instead of "natural" would be any better. Anyway, history has the name NSK and a change would now make access to the prior texts unnecessarily tough.

(For those considering a renaming nevertheless: It should properly address all existing and all future variants of superko.)

I'm just one guy, but the way positional and situational are used in these terms almost exactly matches my intuitions. It's not enough that I can read the phrase "situational superko" and derive the definition from that, but still enough that situational seems like exactly the right word.

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Occupy Babel!

I agree, after hearing of superko it made sense. Then hearing there were two types I was a bit confused, but once the difference was pointed out the two names made perfect sense. In the past I am also guilty of occasionally responding "Whose turn is it?" when when asked "What do you think of this position?" which would suggest to myself that I consider move ownership to be outside of a position.


I can only assume natural superko would be just like other superko but also include 0 (=

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

Visualize whirled peas.

Everything with love. Stay safe.

Of course we are. In most other games situation and position are used interchangeably. So at what point did this sudden break occur?

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North Lecale

The meanings of situational superko and positional superko seem completely intuitive to me. Of course position and situation can be synonyms, and were primarily synonyms in the past, but their primary meanings now differ. The primary definition of situation is now "a set of circumstances in which one finds oneself," whereas the primary definition of position is "a place where someone or something is located or has been put" (according to oxforddictionaries.com).

I hope I'm not just blinded by already knowing these terms.

See my earlier message.

So, the distinction was only made to create 2 flavours of superko?

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North Lecale

Not to create them but to give them names.