Bill: These two examples, I think, show that the rules makers did not understand Honinbo Shuwa's thinking behind his ruling on torazu sanmoku. Since CGT gives the same result for it as Shuwa did, I think that he determined it by local play in the same way as you would determine the result of capturing a dead stone by local play. I. e., the same way that Lasker-Maas rules and Spight rules would, with each player making the same number of plays or passes, and a pass costing one point.
@ , = pass (costing 1 point)
(Note that in the local region White cannot contest the ko.)
Black gets 1 point of territory, 6 captives, and 1 point for White's final pass, for a total of 8 points.
White gets 3 points for 3 captives.
Net result: 8 - 3 = 5.
The results are different for this one, because Black's under the stones play is not effective.
Black gets 1 point of territory plus 5 captives, for a total of 6 points.
White gets 1 point of territory plus 2 captives, for a total of 3 points.
Net result: 6 - 3 = 3
I think that Shuwa would have ruled that the second example is worth only 3 points.
Bildstein: Perhaps Shuwa played a difference game for torazu sanmoku and came to 3 points. Perhaps he decided that all five stones were dead, there was no territory, and a net 3 prisoners giving 3 points. I'd love to know. Perhaps torazu gomoku gives us a clue. Do we have any idea what the rule makers reasoning was when making these two decisions? I can't come up with any logical link between the three judgements.
Bill: I think that Shuwa considered torazu sanmoku as similar to a snapback. Surely he did not have a difference game in mind. ;-) Lasker-Maas rules produce the same result when there are no ko threats, and surely Lasker did not have a difference game in mind, either. With Lasker-Maas rules torazu sanmoku is conceptually the same as a snapback (except for the ko).
I suspect that the 1949 ruling for the two torazu gomoku positions is based on the similarity with torazu sanmoku. The result is 3 points for torazu sanmoku when the player with more stones plays first, and it is 5 points for both torazu gomoku positions when that player plays first. Perhaps that's what gave rise to the ruling.
However, that reasoning offends our sense of fairness, and is absent in the Japanese '89 rules. But because it is unfair, I do not think that it was Shuwa's reasoning.