During centuries, in China and japan, go was played using territory counting, with no official ruleset. When an ambiguous shape appears, the problem is solved asking for the judgement of a third person.
The first complete official ruleset was the japanese one of 1949. It is huge (more than 50 pages ?), and tries to cover each and every exceptional configuration, although it is impossible, since there can be an infinity of them.
These rules are the ones that are the closest to the tradition of go, but they are a nightmare to use for federations that need to publish them (people who are new to go might just run away at the mere sighting of the rules), for the referees who must study them in order to help people during tournaments, and especially for programmers, who can't write any go software that follows them all.
Then, in 1975, China came with a much simpler ruleset using area counting. It is simple and clear, to the satisfaction of federations that must publish it and give it to the referees, and it can be easily programmed into softwares. But on the other hand, it is extremely heavy for the players, who have to count all the area at the end of each game.
Let's skip Ing's rules and New Zealand rules to go directly to the AGA rules, in 1991, that feature the simplicity of the chinese rules, and ask for just a little effort from the players : to give a prisonner when they pass and to have White make the last move.
The players usually don't care about rules. It is the go federations that must face this problem, and also the programmers.
Japanese-style rules have unsolvable theoretical problems, that occurs in one game out of 1000. A go federation can't seriously adopt them. The Nihon Ki-in has been criticised for doing so, and some players (Go Seigen) even demanded that they change that. Which was done in 1989... for the worse !
But since problems occur so rarely, the players themselves are perfectly ok with these rules.
Chinese style rules give no problems to any federation of programmer, but they strongly annoy the players in each and every game.
AGA rules seem to get the best of both worlds. Maybe the part that deals with life and death at the end (touching dead chains while handing prisoners) is too much. French and UK versions of the AGA rules have dropped this part.
RobertJasiek wrote:goTony wrote:When players have a contention at the club the consensus is play it out.
If playout is imagined or undone, this is possible.
Not always : if there is a seki of small value together with a four bent of higher value at the end of the game, for example, the four bent can only be killed sacrificing the seki.
Using imaginary play to prove that the four bent are dead, we come to the conclusion that the seki is dead in imagination, and that once the stones are removed, the intersections become imaginary territory for the opponent !
The 1949 japanese rules had an exception for this shape.
The 1989 japanese rules solved the problem introducing a new rule : ko fights are forbidden during imaginary play.
Chinese and area rulesets allow to play it out thanks to the use of area scoring, that permits real play-out.