For the Japanese, sumo wrestling is not just a sport. It is the essence of their national identity; a 1,500-year-old tradition infused with the rituals and ceremonies of the ancient Shinto religion. For the rest of us, it’s basically two fat guys in diapers trying to smash the living daylights out of each other.

The guys are properly known as rikishi, and while they are certainly big, only someone very brave or very stupid would call them fat — within earshot. Their enormity is the result of years of strict diet and intensive training. In their complete devotion to their calling, rikishi are more comparable to monks than modern sportsmen.

As for the diapers, the correct term is mawashi — a 10-yard long, 2-foot-wide silken loincloth wrapped securely around the rikishi’s vast girth. This single item of clothing is also a sumo fighter’s principal weakness, for it provides his opponent with a grip-hold with which to heave him out of the circular ring, known as the dohyo. There are no second chances when that happens. The moment one of the wrestlers sets foot outside the ring, the bout ends and the victor is declared.

From start to finish, the average sumo bout lasts six seconds.

But the fight is merely the icing on the cake. For a true sumo fan, the best of the drama is played out beforehand. The pre-fight rituals can last up to five minutes. Fans watch every movement, every gesture intently. It is often possible to gauge in these tense minutes which fighter will triumph.

The sumo wrestlers enter the ring from opposite sides, drink holy water for purification, then face each other in the mother of all staring contests. From time to time, the rikishi will walk to one side, scoop up a handful of salt from a basket, and toss it onto the sandy surface of the fight arena. Officially, they are purifying the ring, but they are also psyching each other out.

Finally the two men come to the center of the ring. The bout starts when they touch the ground with their hands. Then they launch into each other: a collision that probably registers on the Richter scale. There are around 70 formal moves by which they can propel their adversary out of the ring. Sometimes they use their opponent’s weight against him, hauling him off balance. Or they can go for sheer brute force, lifting the other man up and dumping him on his ample behind (at considerable risk to spectators with ringside seats).

The bouts take place within a 15-day tournament known as a basho. A fighter’s win record during a basho determines his place in the overall rankings. There are eight ranking levels; the very highest being yokozuna. In the past 300 years, only 62 rikishi have reached yokozuna level.

The first foreign yokozuna was an American, Chad Rowan from Hawaii, who achieved the hallowed status in 1993 under his official name, Akebono. Many Japanese were unconvinced that a foreigner could exhibit the dignity required of a yokozuna. In Akebono’s wake, there has been an influx of foreign rikishi, mainly from Central Asia and Eastern Europe. The only currently active yokozuna is Asashoryu Akinori, from Mongolia. In 2003, he caused scandal by messing with the hairdo of another fighter during a bout — he was disqualified from the basho.

Can a foreigner ever be true to the ideals of sumo? It is a hotly debated topic among Japanese sports fans. If you find yourself in Japan during a major basho, by all means go along. You’ll be welcomed, and it’s a spectacle you’ll never forget. But leave the fighting to the fat guys in diapers. For schedules and ticket information, visit http://www.sumo.or.jp