Since there is so much hype about the official examples II.16-18 in the official commentary on the Japanese 1989 Rules, let me provide a copy from my scrapbook, which is not proofread carefully and contains several inconveniences. Concerning application of the Japanese 2003 Rules to these examples, it essential reading though.

I use shorthand annotation for the hypothetical-sequences and especially these abbreviations:

<34> := last proofread for J2003 / version 34
P := ko-pass (generic ko-pass of J2003)
X := ko-pass for the intersection X (J1989 style ko-pass)
U := uncapturable
[]* := repeated infinitely



Japanese 2003 Rules Application


Example 4602 (II.16)
<34>
11x6
F5




Example 4603 (II.17)
<34>
9x8
F5?




Example 4604 (II.18)
<34>
8x5
F5




Intended Differences between the Japanese 1989 Rules and the Japanese 2003 Rules

Ko-pass Rules and False Status Assessment

In some positions, application of the Japanese 1989 Rules with their ko-pass for a particular ko rules contradicts the official commentary on the Japanese 1989 Rules while application of the Japanese 2003 Rules with their ko-pass for all kos rules agrees to the official commentary on the Japanese 1989 Rules. This change from contradiction to agreement is an intended difference.


Example 6106 (II.16)
11x6
F5? [---]




Example 6107 (II.17)
9x8
F5? [---]




Failure of the Official Commentary on the Japanese 1989 Rules


Example 6701 (II.16)
11x6
F5




[The following hypothetical-sequences might have incorrect intersection letters because I changed them in the diagram at some time.]
- The official commentary says: "The ten white stones in the [upper left] are dead. The twelve white stones on the [right] also die through collapse of the seki."
- Obviously, with "the seki" the commentary refers to the double ko shape on the right.
- The Japanese 1989 Rules do not have any concept "collapse of a seki". So one can only conclude that, regardless of the apparent seki-like shape on the right, the white stones on the right are dead. Since analysis of an independent double ko coexistence shows only the involved ko stones to be dead and the other involved strings to be alive, the reason for death of all white stones on the right must be found in the upper left.
- The official commentary claims that all the ten white stones in the upper left were dead. Let us concentrate on the big upper white string. Black can try to capture it: #[b][gjIHihGJ]*, #[bgjIedciHkpp], etc. Black fails. So the big upper white string is uncapturable alive. The official commentary is wrong.
- This mistake in the official commentary might also explain its second mistake: to conclude that due to the falsely assumed removability of all upper left white stones the right white stones could be dead, too.
- There is a slight possibility that the imprecise wording of the Japanese 1989 Rules' ko-pass rule would prohibited only "immediate recapture in a ko" for some meaning of "immediately" and therefore allow #[bgjIedcihGeDfpp]. However, such a meaning of "recapture" is improbable because §6 speaks of "recapture in that ko on the next move" while §7.2 speaks of "recapturing in the same ko is prohibited" (i.e. no "on his next move" is in the text here) and "may [...] capture in that ko again after passing once for that particular ko capture" (i.e. "capture" is used and not "recapture").
- Suppose that the translation was sufficiently weak and the original rules text was clearer about "recapturing", what would be the exact meaning of "immediately" for that purpose? A possible direction of interpretation could be as follows: A ko-pass would not be necessary for recapturing in a particular if in between the last capture in it the player to recapture has made a play that is not a ko-capture in any ko before recapturing in the particular ko.

Also see

http://home.snafu.de/jasiek/j1989c.html
http://home.snafu.de/jasiek/j2003com.html

Just for the people coming in and to avoid confusion... There are no official Japanese 2003 rules. These are Jasiek 2003 rules.

Comparison of Status Assessments

In the following, status statements refer to the related strings only - not to the trivially alive surrounding groups.

II.16

Official J1989 commentary:
- [All white strings are dead.]

J2003:
- All white strings are dead.
- All black strings are alive.

J1989 application with J1989 ko-pass rule:
- The big white string on the right is alive.

II.17

Official J1989 commentary:
- [All white strings are dead.]
- The three black stones in the corner are alive.

J2003:
- All white strings are dead.
- All black strings are alive.

J1989 application with J1989 ko-pass rule:
- The big upper white string is alive.

II.18

Official J1989 commentary:
- [All black strings are dead.]

J2003:
- All black strings are dead.
- All white strings are alive.


Conclusions

- J2003 always determines the stated statuses in the official J1989 commentary.
- J2003 explains more statuses than the official J1989 commentary.
- The official J1989 commentary provides invalid reasons.
- J1989 application with J1989 ko-pass rule creates statuses that contradict those of the official J1989 commentary.
- The success of J2003 surpasses the previously set principles: J2003 works correctly even for those immaterial examples.
- J2003 explains the examples better than both J1989 and the official J1989 commentary.

oren, indeed. Since the Japanese 2003 Rules application creates correct results where the Japanese 1989 Rules create wrong results, application of the Japanese 1989 Rules ought to be overridden by application of the Japanese 2003 Rules. The non-official rules beat the official rules.

I'm sure the Jasiek 2003 rules are great. Maybe somebody will eventually use them. Good luck to you.

I would rather like to see usage of Area Scoring or else WMSG Rules / Button Scoring or else something like the Simplified Japanese Rules. Application of J2003 (above formal low-level usage of hypothetical-strategy) in practice is useful essentially only as long as J1989, WAGC, Korean 1992+ Rules are still official and in use. Otherwise J2003 (like J1989, WAGC, Korean 1992+ Rules) is more useful for research in go terms than for playing.

Some additional remarks in RED, related to what is a contradiction to the official J1989 commentary only.

II.16

Official J1989 commentary:
- [All white strings are dead.]

J2003:
- All white strings are dead.
- All black strings are alive.

J1989 application with J1989 ko-pass rule:
- White's two-stone string is alive.
- White's seven-stone string is alive.
- The big white string on the right is alive.


II.17

Official J1989 commentary:
- [All white strings are dead.]
- The three black stones in the corner are alive.

J2003:
- All white strings are dead.
- All black strings are alive.

J1989 application with J1989 ko-pass rule:
- White's corner string is alive.
- The big upper white string is alive.

II.18

Official J1989 commentary:
- [All black strings are dead.]

J2003:
- All black strings are dead.
- All white strings are alive.

J1989 application with J1989 ko-pass rule:
- Black's corner string is alive.
- Black's big right-hand string is alive.

_________________
The really most difficult Go problem ever: https://igohatsuyoron120.de/index.htm
Igo Hatsuyōron #120 (really solved by KataGo)