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TwoStageKo

 

Two step ko Two stage ko Discussion
    Keywords: Ko

November 12, 2003

[Diagram]
Two-something ko

Bill: The question of what to call this ko has arisen again on Andre Engels home page. As it turns out, last week I took a look in the 2001 edition of the Go Players Almanac, where this ko is called a two stage ko, and the approach ko is called an approach ko. As two step ko has caused confusion, I propose that we go with the usage in the Almanac, and avoid the term, two step ko altogether.

DougRidgway: My vote would be to always include either iterated or approach: with step or stage alone, I'm never sure what is meant, there's too much usage going both ways.

Bill: You only need to use stage with an approach ko if it is a compound ko. E. g., a two stage one move approach ko. The phrase that caused the current confusion, on the Carpenters Square page, was a mistake. The ko is a three move approach ko. Not even close. Otherwise, two stage ko had an unusual usage here for a ko where one player can make a bent-four shape and create a new ko from that. Quite arguably, that is a two-stage ko. :-) However, it is also a rogue ko, and I went ahead and changed the references. In no case did I find anyone using two stage ko for a one move approach ko, unlike has happened with two step ko. So I do not think that there is as much confusion over that term.

Andre Engels: I agree that the best strategy would be to not use the term 'two step ko' at all. As far as I know, the terms 'one move approach ko' and 'two stage ko' are unambiguous. My proposal would be to write a small bit on the controversy on Two step ko, plus references to Approach ko and Two stage ko, and a remark to readers that if they find a page linking to it, it would be better to change the link to refer to one of those pages.

Andre Engels: Hmmm... Seeing below that there are people actually _swapping_ the meanings compared to Davies, maybe it would be better to rename two stage ko as nidan ko as well.

Bill: I am not as nihongophobic as Charles, but I think we shouldn't go with nidan ko, even if it is unambiguous. Do we expect people to learn to count in Japanese, so they can say, rokudan ko?

I dislike n-stage ko because, as an English speaker, calling each ko capture a stage seems weird to me. Wrong metaphor. But I think that it is good to have standards, and the latest Almanac is good enough.

April 30, 2003

DougRidgway Looks like the toplevel pages haven't converged yet. For anyone interested in reading discussion, here's a link to the 2002 rgg thread on this topic:

[ext] thread

14 February: Bill: Happy Valentine's Day!

I do not mind if the local dialect avoided using two step ko entirely, given the unfortunate ambiguity in prior English usage. However, the paragraph comparing unfavorable "two step kos" and "two stage kos" is poorly written, at best, if not downright misleading. I say, cut it.

11 december: Bill and Andre Engels, would it be possible to merge the pages TwoStepKo and TwoStageKo? They look awfully similar and I have the impression, that the definitions are very closely related. Wouldn't it make sense to define TwoStageKo as an alias to TwoStepKo and add the difference to that page? It also would help, if you could add an example of the type "This is a two step ko but not a two stage ko" (or the other way round) for weaker players like me who have trouble grasping the difference.

Another possibility would be to move the whole content to a page Nidan Ko and have both TwoStepKo and TwoStageKo refer to it as aliases.

--Confused

10 december: I wonder if a two stage ko (one player needs to win 2 ko depending on each other) just a variant of an approach ko or a beast of its own kind. Should two stage ko get their own page or should they just be referred to the ApproachKo page? --Confused

It's a different notion. Charles Matthews

See TwoStepKo. -- Bill

That page is awfully incorrect. What is shown there is a two stage ko. A two step ko 'is' the same as an approach move ko (with one approach move). -- Andre Engels

Bill: Cut it out, Andre. Nidan ko = 2-step ko. Ni = 2. Dan = step. It is *not* the same as a 1 move approach ko (itte yose ko). In fact, there is such a thing as a 2-step 1-move approach ko. :-)

Apparently there is a bad translation somewhere, but that is no reason to perpetuate the error. In a recent note in rec.games.go, Simon Goss recommends saying two-step iterated ko, three-step iterated ko, etc. There was some discussion about whether to talk about 2-stage kos. That seems ambiguous to me, since there are 2 stages to a 1-move approach ko. Equitable ko threats are larger in the second stage.

Charles Matthews My favoured approach now to cyclic positions taxonomy doesn't solve problems of nomenclature (yet).

I don't care what the translation of "dan" is. The English go term means what the go term is used for in English, not what the translated go term means in Japanese. -- Andre Engels

It depends how widespread the use is. I guess many of us were bred with James Davies. It is not guaranteed that future generations and other nationalities read Davies. Therefore, if translations and interpretations lead to ambiguity, we can overrule what has been common use. Dieter



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