Ikeda's superko?

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luigi
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Ikeda's superko?

Post by luigi »

Footnote (by James Davies) found in Ikeda Toshio's On the Rules of Go:
Actually, under Ikeda's formulation of the super-ko rule Black A is allowed because it is not a capturing move. Rule 4 in Part I states that, "If playing on a grid point places any stones of the other color in a removable state, the configuration resulting from removal of those stones must not be identical to a configuration that has already appeared in the game." Rule 4 may have been worded in this way to avoid awkward sentence structure in Japanese. Judging from Dia. 3-2-10 and the discussion in section 3.3, Ikeda intended the super-ko restriction to apply to all moves, not just capturing moves.
I never thought of applying superko to capturing moves only, but it does seem interesting, even if it's not what Ikeda meant. For one, it blends in nicely with the ko rule and makes illegal moves a bit easier to spot. I haven't seen this rule discussed anywhere, though.
asura
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Re: Ikeda's superko?

Post by asura »

luigi wrote: I never thought of applying superko to capturing moves only, but it does seem interesting, even if it's not what Ikeda meant. For one, it blends in nicely with the ko rule and makes illegal moves a bit easier to spot. I haven't seen this rule discussed anywhere, though.
Ing ko rules work that way, though in a modified way. (Of corse, this would be a bad example, if you want to show that this rule makes it more easy :)

I believe your idea would work fine and would lead to the same outcome as a normal superko rule in allmost all positions. Probably it would make a smaller difference than switching between PSK and SSK.
Pio2001
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Re: Ikeda's superko?

Post by Pio2001 »

The bad side is that the definition is more complicated than positional superko.
What is the good side ?
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Re: Ikeda's superko?

Post by asura »

I wouldn't call this rule more complicatet.
You need only to check for super-ko, when you make a capturing move. If a move is a capturing move is trivial to check. So you will have either less work (for the moves that doesn't capture anything) or you will have to do the same work (for the capturing moves).
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Re: Ikeda's superko?

Post by redreoicy »

This superko rule breaks eternal life, which normally becomes equivalent to a ko under superko rules.
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Re: Ikeda's superko?

Post by asura »

redreoicy wrote:This superko rule breaks eternal life, which normally becomes equivalent to a ko under superko rules.
I think this version of superko would only shift the points, when the players need to make a ko-threat, so this should be still equivalent to a simple ko.
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