[Version 3; 2008-04-23; Robert Jasiek; free copy and application]
[Basic definitions are omitted.]
A move is either a play or a pass.
A move-sequence is a sequence of alternating moves and ends by two successive passes.
The alternation is a move-sequence starting by Black from the empty board.
The analysis is a move-sequence continuing the alternation. Afterwards the position at the end of the alternation is restored.
The game consists of the alternation, then the optional analysis, and then the game end.
Prisoners are the stones removed during the alternation or the game end.
Suicide is prohibited.
A play may not recreate a position just after any earlier play.
A two-eye-formation is a set of one or several strings of the same player and exactly two empty intersections so that each of the strings is adjacent to each of the two intersections, none of the strings is adjacent to another empty intersection, and each of the two intersections is adjacent only to the strings.
A player's string in the position at the end of the alternation is independently alive if the analysis has created a two-eye-formation of his on at least one of its intersections.
If the players agree, they remove stones accordingly. Else they consider the connected regions that are adjacent only to one player's independently alive strings and that consist of intersections being empty or having opposing not independently alive strings on, which they remove.
A player's territory is the number of intersections of connected empty regions adjacent only to his strings.
The score is Black's territory plus prisoners of white colour minus White's territory, prisoners of black colour, and the komi.
Black wins if the score is greater than zero. White wins if the score is smaller than zero. The game is a tie if the score is zero.
The rules are not traditional any more because life is determined for all strings together (not locally for each string or each "group" of strings) by the players' skill (not by reference to perfect play), superko is used, there is territory in sekis, and there are no extra phases for dame and teire or resumption. At the same time, the rules are about the simplest one could get while still referring to life concepts at all in the rules (further simplification would result in something like Ikeda Scoring or New Amateur-Japanese Rules).
The simplification illustrates the core of unnaturality of Japanese style rules: there is a distinction between alive and not alive strings at all (Area Scoring simply refers to strings being on the board), game end removals come only from in between one player's alive strings (instead from everywhere), and there are different rules for the alternation and the analysis at all (filling of one's territory is costly versus free).
There is territory in sekis, and this allows a beautifully simple definition of territory. Stones from sekis should be removed during the alternation. In rare positions like hane-sekis, it can happen that stones cannot be removed and there is no territory next to capturable but not removed stones in sekis.