3.3 Recreating the Same Position after a Pass (4)
Next let's consider what happens if recreating a former position is
allowed after consecutive passes. This is the most important case,
because rules theorists have proposed solving the problem of connecting
a final ko by ending the game with three passes.
The next example shows that even this rule does not solve the problem.
In Dia. 3-6 there is a bent four in the bottom right corner, which of
course we do not consider to be unconditionally dead. If Black connects
the thousand-year ko in the top right and an exchange takes place, or
if Black takes but does not connect the ko at 'a' and White tries to
capture the bent four in the corner, White loses by one point.
95 captures 94, 96 passes, 97
at 'a,' 98 passes, 99 passes
After Black 97 takes the thousand-year ko at 'a' Black does not connect
this ko, because the game would then end in a draw. After White and
Black pass, if White retakes the ko and Black and White both pass, Black
can then recreate the same position two lines below White 94, and White
will be unable to recreate the same position by recapturing, so White
will die an unnatural death. Therefore, White does not recapture the
If Black accordingly declares that he is not going to connect, then
the ko at 'a' is left hanging and we have the problem of whether the
point below 'a' is Black's territory or not. We are forced to conclude
that the rule to end the game with three passes, in order to solve the
problem of connecting a final ko by allowing exceptions to the super-ko
rule after two passes, does not solve the problem of connecting the
final ko in Dia. 3-6.
Under area rules Black gains a point by connecting the ko, so Black will
connect the ko and the problem will be solved quite simply.
This is an important position. The thousand-year ko, the bent four
in the corner, and the position in the top left in Dia. 3-6 are not
particularly unusual. It is not like the positions in Dias. 3-3-1 and
3-3-3 in which all groups have just two eyes, a situation which will
virtually never arise in actual play.
Various other exceptions to the super-ko rule might be considered. For
example, after two consecutive passes, you could allow former positions
to be recreated just twice. But there are any number of examples in
which this yields a strange result with a repeating cycle halted in an
odd state. Making exceptions to the rule only serves to create unnatural
cases. There is no telling what sort of anomalies may turn up.
In short, the super-ko rule is one of the fundamental rules of go, and
making exceptions to it can lead to troubles that are hard to foresee.
If you feel that results such as Dias. 3-3-2 and 3-3-4 run counter to
tradition and you make exceptions to the super-ko rule to accommodate
them, you had better be ready to prove by logic that your exceptions do
not cause trouble. It will not be enough to say that no cases have been
found in which the exception leads to peculiar results. That argument
will always leave doubts about the rules.
My opinion is that go has three fundamental rules which should be common
to all rulesets and to which no exceptions should be allowed. These are:
||The rule of alternate play (where play means playing a stone on the board or passing)
||The capturing rule
||The super-ko rule
Having exceptions in territory rules and not having exceptions in area
rules would not promote the future establishment of an international set
- Ikeda's argument is a little hard to follow. He appears to have
switched back to territory rules. Under area rules, if White plays 96 in
the lower right corner to start a ko to capture the bent four, Black has
to give up his stones in the top left corner to save the bent four, and
White wins the game by one point. Alternatively, Black can play 'b' as a
ko threat, but White answers this ko threat, then trades the white group
in the top left for the black group in the bottom right and wins by even
A simpler argument against allowing recreation of a former position
after two consecutive passes is that the player who is losing could
prolong the game infinitely by repeatedly capturing a double ko, if
there is a double-ko seki on the board.