I think that anywhere around the world, if you ask, which sport is typically Japanese, you'll get the same answer: sumo! :) Of course, there are sumo wrestlers in other countries (as far as I know, there are also sumo tournaments here, in Poland, but it's not very popular). I wonder, if this sport has rather positive or negative influence on health and do the wrestlers try to lose some weight, when they stop training sumo?
Sumo (相撲) is a competitive contact sport where a wrestler (rikishi) attempts to force another wrestler out of a circular ring (dohyo) or to touch the ground with anything other than the soles of the feet. The sport originated in Japan, the only country where it is practised professionally. The Japanese consider sumo a gendai budō (a modern Japanese martial art), though the sport has a history spanning many centuries.
The sumo tradition is very ancient, and even today the sport includes many ritual elements, such as the use of salt for purification, from the days sumo was used in the Shinto religion. Life as a rikishi is highly regimented, with rules laid down by the Sumo Association. Professional sumo wrestlers are required to live in communal "sumo training stables" known in Japanese as heya where all aspects of their daily lives—from meals to their manner of dress—are dictated by strict tradition.