[2] He gained his first major regional medal at the 1993 East Asian Games in May, where he took a silver with a jump of 7.93 m to finish behind Nai Hui-Fang.

Asahara represented Japan at the 2008 Summer Olympics in Beijing, competing at the 100 meters sprint.

[8] The medal was upgraded to a silver after the Jamaicans were DQ'ed due to Nesta Carter's positive doping sample.

On 23 September 2008, he retired from competitive athletics at the Kawasaki Super Meet, finishing third in the 100 m behind Mark Lewis-Francis and Michael Rodgers.

After being greeted on the podium by Usain Bolt, Asahara said "It wasn't my best race, but it was exciting to run in front of so many fans.

"[9] After his retirement he was employed by Osaka Gas and opened an athletics training camp for children.