Javaness2 wrote:
can you actually tell these 3 flavours of ko apart, without referring to their definition?
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".
Bill Spight wrote:
As for natural, that is PR, isn't it?
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.)