I'm curious whether the league game today between Yi Se-tol and Jiang Weijie was treated as a triple ko or quadruple ko. If the latter I'd expect a bigger fuss about it.

In passing, this game shows once again that the rule about superko is ignored. This game was treated as void and replayed.

I'm curious whether the league game today between Yi Se-tol and Jiang Weijie was treated as a triple ko or quadruple ko.

Just to clarify, the E10/F10 ko doesn't really matter right? That's just a 1 point ko, it's the double ko at R7/8 and T7/8 combined with the critical ko at A1/2 that caused an impasse right? Because if either of those groups die that player loses?

How can you ignore a rule that doesn't exist for the competition?

... is it close enough that that 1 point ko decides the game?

I no longer try to keep abreast of the wrinkles but as I understand it superko does exist as a rule in Chinese Go Association rules. It's just that nobody seems to take any notice of it usually. Macelee may be able to explain the finer points.

A practical point is that if Chinese players ignore the rule, then should those playing under AGA and similar rules do likewise?

FWIW, on a study trip to China we (European amateur) students had to explain the superko rule to our (Chinese professional) teachers.

A rough translation to the relevant section of the Chinese rule:

Repeated board positions (such as triple ko, quadrupal ko, eternal life etc) are forbidden in principle. Depending on tournament, these games may be declared as void, draw or replay ordered.

So it is incorrect to say that the Chinese players simply ignore the rule.

Concerning professionals, superko has been used in Ing-I Rules, Chinese Rules (for sending-2-returning-1 for sure, also CEGO), Japanese 1949 Rules (in the text only).