By Chris Hogg
BBC News, Tokyo
Both Roho (L) and Hakurozan (R) deny using marijuana
In Japan the world of sumo wrestling has been rocked by a drugs scandal.
Two Russian wrestlers have tested positive for marijuana use and another has been arrested on suspicion of possessing the drug.
The wrestler who was arrested has already been banned for life. The other two are waiting to hear how they will be punished.
The world of sumo is very conservative and wrestlers are held to the highest moral standards.
The sport's governing body has taken swift and tough action against a 20-year-old Russian, known by his fighting name of Wakanoho, who was arrested on suspicion of possessing cannabis.
WHAT IS SUMO?
Sumo is Japan's national sport, dating back hundreds of years
Two wrestlers face off in an elevated circular ring
They try to push each other to the ground or out of the ring
Wrestlers are ranked, and the highest level is yokozuna
He was caught after the wallet which he had lost was found and handed in to the police. They found a cannabis cigarette inside.
He was arrested and now faces up to five years in prison with forced labour.
The Sumo Association banned him for life, the first time an active wrestler has been kicked out of the sport.
Random drug tests have been carried out on 69 wrestlers at the top of their sport.
Two other Russians, Roho and Hakurozan, tested positive, although when police searched their rooms they did not find any drugs.
The two have denied smoking marijuana and asked for their samples to be retested.
Japan's Cannabis Control Law outlaws the possession but not use of the drug so the two wrestlers cannot be prosecuted.
It seems likely, though, they will face tough sanctions from the committee which controls the sport.