which media attention has focused on match
rigging. The rst of these was in April and May
of 1996. A former sumo wrestler who had be-
come a stable-master came forward with alle-
gations of match ri gging. At the same time,
another former wrestler also came forward to
decry rigged matches. Ironically, both of these
men died a few weeks later, just hours apart, in
the same hospital. T his fueled speculation
among the media of foul play, although a sub-
sequent police investigation revealed no evi-
dence for th is. The second period of media
scrutiny took place in late 1999– early 2000. A
former sumo wrestler named Itai rai sed allega-
tions of match rigging that were wid ely covered
by the media, even in the United States. The
three tournaments in our sample that are most
likely to be affected by the media attention are
those held in May 1996, November 1999, and
January 2000.
The literature on repeated-play games (e.g.,
Drew Fudenberg and Jean Tirole, 1991) sug-
gests that the ability to sustain collusion should
be positively related to the frequency with
which two wrestlers e xpect to meet in the future
since more future meetings imply the availabil-
ity of more severe punishments for wrestlers
who d o not cooperate. Empirically, we p roxy
the expected frequency of future m atches using
two variables: (1) the number of meetings be-
tween the two wrestlers that took place in the
preceding year, and (2) whether the wrestler is
in the last year of his career. Although the
precise ending of a wrestler’s career is not
known in advance to the participants, it is likely
that signals of retirement are available (e.g.,
declining performance, injuries, etc.).
10
If it
takes time t o establish a reputation as a wrestler
who is willing to collude and who can be
trusted, then one might predict that the longer a
wrestler has been active in the top ranks of
sumo, the better he will do when he is on the
bubble, and also, the worse he will perform
when the opponent is on t he bubble.
Because there are a series of monetary prizes
given to wrestlers who have good records in a
given tournament, wrestlers in the running for
such prizes are unlikely to be willing to throw
matches.
11
The overall tournament champion
wins $100,000; the
juryo
champion wins
$20,000. In addition, $20,000 awards for “ ght-
ing spirit” and “outstanding technique.” In order
to win those prizes, wrestlers must compile very
strong records. The potential value of a victory
for a wrestler in the running for such prizes is
likely to be at least as great as the value to a
wrestler on the margin for an eighth win.
A n al determinant of match rigging that we
consider is the possibility of coordinated match
rigging among stables of wrestlers. The lives of
sumo wrestlers center around the stable with
which they are associated. Stable-masters exert
a tremendous in uence over both the wrestling
career of wrestlers and their lives more gener-
ally.
12
Given the important role of the stable,
and the fact that stable-masters bene t from
having highly ranked wrestlers, it would not be
surprising if corruption were coordinated at the
stable level. For example, stables might have
collective reputations, with stable-masters en-
forcing punishments on wrestlers who pursue
their individual best interests at the expense of
the stable. Some stable-masters, on the other
hand, may not co ndone match rigging because
of ethical concerns o r risk aversion.
We empirically examine one particular form
of stable-level collusion: the presence of reci-
procity agreements across stables. If such deals
existed, one would expect both that wrestlers
from stable
A
will have very high win rates
when on the bubble facing wrestlers from stable
B
, and v ice versa.
13
It is dif cult to tell an
alternative story that would account for such a
pattern in t he data. For instance, if effort is the
10
In order to minimize endogeneity, we exclude the very
last tournament of a wrestler’s career. It is possible that a
loss on the bubble may drop the wrestler out of the top level
of wrestlers, inducing retirement. Including the last tourna-
ment of a wrestler’s career slightly increased the magnitude
and statistical signi cance of the coef cient.
11
Although we do not directly observe which wrestlers
might be under consideration for these prizes, having one of
the ve best records (plus ties) up until that point in the
tournament is an excellent predictor. Wrestlers with one of
the ve best records in the tournament entering days 13, 14,
or 15 win a prize 50 percent of the time. Less than ve
percent of wrestlers with reco rds outside the top ve on
days 13–15 eventually win a prize.
12
For instance, it is expected that the foremost sumo wres-
tler in a stable will marry the daughter of the stable-master.
13
The variable we use to test this empirically is the
overall win rate for wrestlers on t he bubble in matches
involving both a wrestler from stable A and a wrestler from
stable B (excluding the current match). This variable re ects
both stable A’s success on the bubble against stable B and
stable B’s success against stable A.
1599VOL. 92 NO. 5 DUGGAN AND LEVITT: CORRUPTION IN SUMO WRESTLING