Bill Spight wrote:Gérard TAILLE wrote:
Another example of very common seki:
$$W 0 point in japonese rule and 1 point in Spight rule
$$ --------------------
$$ | O . O . X O . . . .
$$ | X O O . X O . . . .
$$ | X X X X X O . . . .
$$ | O O O O O O . . . .
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$
- Click Here To Show Diagram Code
[go]$$W 0 point in japonese rule and 1 point in Spight rule
$$ --------------------
$$ | O . O . X O . . . .
$$ | X O O . X O . . . .
$$ | X X X X X O . . . .
$$ | O O O O O O . . . .
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$[/go]
As you mentionned it very clearly yourself, Spight rule is not japonese rule. My view is that the difference concerns essentially sekis with one point difference in some very common cases.
OC it is not a problem Bill just a comparaison for a better understanding.

Basically, Spight rules with territory scoring implement Berlekamp's No Pass Go with Prisoner Return, with a superko rule. Except for the superko rule, it is consistent with the oldest extant game records for which the scores are known, which are territory scores with a group tax. The main difference with modern Japanese scoring is the group tax. Modern Japanese scoring of sekis is also quirky. The SpightJapaneseStyle rules are irrelevant. Why do you keep referring to them?
Yes Bill, I my last post I mentionned only "Spight rule" and not "japonese Spight rule" but may be I was not clear enough.
Bill Spight wrote:
How do you see the shown mannenko position remaining on the board, so that White gets 1 net point in the encore?
Because connecting the ko is a one-sided dame and with encore, any one-sided dame allows to gain one point. Am I wrong?
If it is true (?) then
$$W Japonese rule 0, Spight rule +2
$$ ----------------
$$ | . O O X . . .
$$ | X . O X . . .
$$ | X X O X . . .
$$ | . . O X . . .
$$ | O O O X . . .
$$ | X X X X . . .
$$ | . . . . . . .
$$ -------------
- Click Here To Show Diagram Code
[go]$$W Japonese rule 0, Spight rule +2
$$ ----------------
$$ | . O O X . . .
$$ | X . O X . . .
$$ | X X O X . . .
$$ | . . O X . . .
$$ | O O O X . . .
$$ | X X X X . . .
$$ | . . . . . . .
$$ -------------[/go]
and similarly, assuming no ko fight (I mean no ko threat):
$$W Japonese rule +1, Spight rule +3
$$ ----------------
$$ | . O X . O X . .
$$ | O X X . O X . .
$$ | O O O O O X . .
$$ | X X X X X X . .
$$ | . . . . . . . .
$$ | . . . . . . . .
$$ -------------
- Click Here To Show Diagram Code
[go]$$W Japonese rule +1, Spight rule +3
$$ ----------------
$$ | . O X . O X . .
$$ | O X X . O X . .
$$ | O O O O O X . .
$$ | X X X X X X . .
$$ | . . . . . . . .
$$ | . . . . . . . .
$$ -------------[/go]
2 points difference looks significant and I guess strategy may change if these kind of seki occur.