Analysis16
Are regional basho really more chaotic?
Conclusion
The idea is not supported. The upset rate was 35.7% in Osaka, Nagoya, and Fukuoka, versus 36.3% across Tokyo basho. Venue changes alone do not appear strong enough to move Makuuchi results in a meaningful way.
How to read this number
The three regional tournaments in Osaka, Nagoya and Fukuoka produced a 35.7% upset rate against 36.3% for the three Tokyo tournaments. The gap is small and points the opposite way from the belief.
By tournament, the most volatile is Hatsu in January at 37.9% and the steadiest is Natsu at 34.9%. Nagoya, often blamed on the summer heat, sits at 35.5% and is among the more orderly of the six.
Travel and unfamiliar lodging surely tax the rikishi. What the data says is that the effect is not large enough to move results. An upset in Nagoya is a product of that tournament's matchups, not of Nagoya itself.
Methodology
- Period
- Hatsu 2000 through Natsu 2026
- Sample
- Makuuchi bouts with a strength-index gap of 40 or more before the bout
- Sample size
- Regional 16,140 bouts, Tokyo 16,142 bouts
- Calculation
- Number of losses on the higher side ÷ Number of samples. Local areas 35.7%, Tokyo 36.3%
- by basho
- Hatsu Basho37.9%, Natsu Basho34.9%, Nagoya Basho35.5%
How to read this
Strength index is calculated only before the bout. Differences in seasons, Banzuke, and rikishi compositions other than the venue will remain.