With no offenders in its past Olympic delegations, Japan won support in bidding to host the 2020 Olympic and Paralympic Games in Tokyo due in no small part to its pledge of "cleanliness."

Japan faces challenges of a different dimension, however, as the host nation for a large-scale sporting event involving more than 10,000 athletes from over 200 nations and regions.

"If we discuss the issue merely within the range of Japanese athletes, we would end up like the frog in a well that knows nothing of the great ocean," said Shin Asakawa, chief executive officer of the Japan Anti-Doping Agency.

The International Olympic Committee and the World Anti-Doping Agency reexamine on a continuing basis samples collected in the past, using up-to-date sophisticated technologies.

As a result, more than 100 violations have been detected from athletes who competed in the 2008 Beijing Games and the 2012 London Games. It is significant that such a large number of injustices remained hidden during the quadrennial competitions.

Japan aims to stop doping at the national border. "We must take measures to keep suspicious athletes from the 2020 Games," Asakawa said.

Tainted athletes will aim to take banned substances so that they do not test positive during the Olympics or Paralympics. Decisions on when and whom to test, therefore, make a difference. Australia, at the leading edge in antidoping efforts, is said to detect about 30 pct of offenders by methods other than tests during competition.

The key is intelligence, with the authorities relying on a range of sources.

Global dealers of so-called dangerous, or quasi-legal, drugs often handle substances that work well for athletes. Authorities sometimes obtain information on tainted athletes from such dealers during plea bargaining, as well as from police after criminal procedures are completed, according to informed sources.

"It would be good if Japan can employ such methods," Asakawa said.

A scientific approach is the basis of efforts to prevent athletes from getting way with doping. Sports at high risk of being affected by drug use are prioritized, while information on top athletes' training schedules, entry to competitions and whereabouts is shared among the antidoping authorities of individual nations and regions. (Jiji Press)