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 ApplicationExample 4602 (II.16)<34>
11x6
F5
Code:
final-position
. O O . O . O # . # O
O # # O O O O # # O O
# # . # # O # # O . O
. # # # O # # # # O O
# # O O O O O # # . O
O O O . O . O # # # O
intersections
b c d e O f O # g h O
a # # O O O O # # O O
# # . # # O # # i j O
. # # # O # # # # O O
# # O O O O O # # k O
O O O . O . O # # # O
Hypothetical-sequences and hypothetical-strategy:
Omitted.
Life and death:
The right big black string is U:
O[gjPpihPp]*
etc.
The right big white string is neither uncapturable nor capturable-1:
#[bpedcpePf..]
#[bPedcpePf..]
#[bgjPedcpePf..]
#[bgjPedcihPegf..]
#[bgjPedcihPePf..]
#[bgjPeif..]
etc.
local-2 for each of the white top or right
strings:
2 2 2 2 2 2 2 2 2 2 2
2 2 2 2 2 2 2 2 2 2 2
2 2 2 2 2 2 2 2 2 2 2
2 2 2 2 O 2 2 2 2 2 2
2 2 O O O O O 2 2 2 2
O O O . O . O 2 2 2 2
Each of the white top or right strings is dead:
#[bpedcpePf..]
#[bPedcpePf..]
#[bgjPedcpePf..]
#[bgjPedcihPegf..]
#[bgjPedcihPePf..]
#[bgjPeif..]
etc.
The black string h is capturable-1:
O[gjPbihPedcgjPePf..]
etc.
Other details: omitted.
Hypothetical-analysis:
Omitted.
Determination of the result:
Mostly omitted.
Score = 44
Note:
It is particularly noteworthy that the black string h is capturable-1.
Example 4603 (II.17)<34>
9x8
F5?
Code:
final-position
# # # . O # . # O
. O O O O # # O O
O O O O O # O . O
. O O O O # # O O
O # # # O # # . O
# # # # # O # # #
. # . # O O O O O
# # # # O O . O .
intersections
d e f g O # h i O
c O O O O # # O O
O O O O O # j k O
b O O O O # # O O
a # # # O # # l O
# # # # # O # # #
. # . # O O O O O
# # # # O O . O .
Hypothetical-sequences and hypothetical-strategy:
Omitted.
Life and death:
The right big black string is U:
O[hkPpjiPp]*
etc.
The right big white string is neither uncapturable nor capturable-1:
#[bhkPcgedcPf..]
#[bhkPcgejiPdhkPcfdjiPcechdpp]
#[bhkPcgejidcPf..]
etc.
The upper left black string is not U:
O[cbg..]
etc.
The upper left big white string is neither uncapturable nor capturable-1:
#[bPapcgedcPfpp]
#[bPapcgedchfpp]
#[bPapcgehkPdjiPcfdhkPcecjdpp]
#[bPahkPcgedcPfpp]
#[bpapcgedcPfpp]
#[bhkPcgedcPfpp]
etc.
local-2 for each of the upper and right white
strings:
2 2 2 2 2 2 2 2 2
2 2 2 2 2 2 2 2 2
2 2 2 2 2 2 2 2 2
2 2 2 2 2 2 2 2 2
2 2 2 2 2 2 2 2 2
2 2 2 2 2 2 2 2 2
2 2 2 2 O O O O O
2 2 2 2 O O . O .
The white string a is dead:
#[bPapcgedcPfpp]
#[bPapcgedchfpp]
#[bPapcgehkPdjiPcfdhkPcecjdpp]
#[bPahkPcgedcPfpp]
#[bpapcgedcPfpp]
#[bhkPcgedcPfpp]
etc.
Likewise, the other upper and right white strings are dead.
The black string d-e-f is capturable-1:
O[cbgePahkPdfdpepp]
O[hkPpcbgePafdpp]
etc.
The black string i is capturable-1:
O[cbgePahkPdfdpe..]
O[hkPpcbgePafd..]
O[hkPbjiPahkPcgejiPdhkPcfdjiPcechd..]
O[hkPbjiPahkPcgedcPf..]
O[hkPbjiPahkPcgedcjf..]
etc.
Other details: omitted.
Hypothetical-analysis:
Omitted.
Determination of the result:
Mostly omitted.
Score = 54.
Notes:
It is particularly noteworthy that the black string i is capturable-1.
White should have captured three bent-4 stones during the alternating-sequence.
Example 4604 (II.18)<34>
8x5
F5
Code:
final-position
. O . # O . O #
O # # # O O # #
. # O O O # . #
# # O O O O # #
O O O O O O . #
intersections
c d e # O f g #
b # # # O O # #
a # O O O h i #
# # O O O O # #
O O O O O O j #
Hypothetical-sequences and hypothetical-strategy:
Omitted.
Life and death:
The upper left white strings and the big white string are U:
#[fiPphgPp]*
etc.
The black strings are neither uncapturable nor capturable-1:
O[cpifPpeadcbPepjpgpp]
O[cfiPeadcbPepjpgpp]
etc.
The white string g is capturable-1:
#[fiPchgPaebcdfa..]
#[fiPchgPaebfiPc..]
#[fiPcpaebhgPcfiPadbhgPacaba..]
etc.
local-2 for each of the black strings:
2 2 2 2 2 2 2 2
2 2 2 2 2 2 2 2
2 2 2 2 2 2 2 2
2 2 2 2 2 2 2 2
2 2 2 2 2 2 2 2
Each black string is dead:
O[cpifPpeadcbPepjpgpp]
O[cfiPeadcbPepjpgpp]
etc.
Other details: omitted.
Hypothetical-analysis:
Omitted.
Determination of the result:
Mostly omitted.
Score = -36.
Intended Differences between the Japanese 1989 Rules and the Japanese 2003 RulesKo-pass Rules and False Status AssessmentIn 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? [---]
Code:
final-position
. O O . O . O # . # O
O # # O O O O # # O O
# # . # # O # # O . O
. # # # O # # # # O O
# # O O O O O # # . O
O O O . O . O # # # O
intersections
b c d e O f O # g h O
a # # O O O O # # O O
# # . # # O # # i j O
. # # # O # # # # O O
# # O O O O O # # k O
O O O . O . O # # # O
Is the big white string on the right alive or dead?
The Japanese 1989 Rules:
The big white string on the right cannot be captured:
#[bgjIedciekpp]
#[b][gjIHihGJ]*
etc.
Black has to pass for the ko j if he wants to recapture it after #[bgjIedci]. That the big white string on the right is alive because it cannot be captured contradicts the official commentary on the Japanese 1989 Rules that the big white string on the right was dead.
The Japanese 2003 Rules:
By proposition 4 and despite many enabling-local intersections, the big white string on the right is dead:
#[bpedcpePf..]
#[bPedcpePf..]
#[bgjPedcpePf..]
#[bgjPedcihPegf..]
#[bgjPedcihPePf..]
#[bgjPeif..]
etc.
That the big white string on the right is dead agrees to the official commentary on the Japanese 1989 Rules.
Example 6107 (II.17)9x8
F5? [---]
Code:
final-position
# # # . O # . # O
. O O O O # # O O
O O O O O # O . O
. O O O O # # O O
O # # # O # # . O
# # # # # O # # #
. # . # O O O O O
# # # # O O . O .
intersections
d e f g O # h i O
c O O O O # # O O
O O O O O # j k O
b O O O O # # O O
a # # # O # # l O
# # # # # O # # #
. # . # O O O O O
# # # # O O . O .
Is the big upper white string alive or dead?
The Japanese 1989 Rules:
The the big upper white string cannot be captured:
#[b][hkJIjiHK]*
#[bhkJcgejIlpp]
etc.
The ko-pass rules are unclear, so in case #[bhkJcgejiHcdDfpp] [---] should be legal it does not capture the big upper white string, either.
That the big upper white string is alive because it cannot be captured contradicts the official commentary on the Japanese 1989 Rules that the big upper white string was dead.
The Japanese 2003 Rules:
The the big upper white string is dead:
#[bPapcgedcPfpp]
#[bPapcgedchfpp]
#[bPapcgehkPdjiPcfdhkPcecjdpp]
#[bPahkPcgedcPfpp]
#[bpapcgedcPfpp]
#[bhkPcgedcPfpp]
etc.
That the big upper white string is dead agrees to the official commentary on the Japanese 1989 Rules.
Notes:
The other white strings are not discussed here. See elsewhere.
Failure of the Official Commentary on the Japanese 1989 RulesExample 6701 (II.16)11x6
F5
Code:
final-position
. O O . O . O # . # O
O # # O O O O # # O O
# # . # # O # # O . O
. # # # O # # # # O O
# # O O O O O # . O O
O O O . O . O # O O O
intersections
b c d e O f O # g h O
a # # O O O O # # O O
# # . # # O # # i j O
. # # # O # # # # O O
# # O O O O O # k O O
O O O . O . O # O O O
[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.htmlhttp://home.snafu.de/jasiek/j2003com.html