The results of all random drug tests conducted in sumo from April through October have come back negative.
The Japan Sumo Association said Sunday all 309 association members tested from 18 sumo stables in the final three rounds carried out during October were clean.
"Firstly I am relieved but this is not the end and I want the tests to continue being carried out again next year," said Isenoumi, who heads a directive board to rid sumo of illegal drugs and other problematic elements which have recently tarnished the image of the ancient national sport.
Mitsubishi Chemical Medience Corp., Japan's only institution certified by the World Anti-Doping Agency, was in charge of examining all of the urine samples.