Former WBA flyweight champion Takefumi Sakata announced his retirement from the ring on Thursday.
"I have felt my body weakening and I can't battle on anymore," Sakata told a news conference. "I am filled with a sense of achievement. I want to think about which path my future will take."
Sakata won the WBA fly crown in his fourth crack at a world title in March 2007. He successfully defended the title four times before losing to Denkaosen Kaowichit of Thailand the following year.
The 30-year-old took on champion and compatriot Daiki Kameda in September last year but lost what turned out to be his final bout by unanimous decision. He finishes his career with a 36-6-2 record (17 knockouts).
Looking back over his career, Sakata said he had gained confidence after making his first attempt at a world title in June 2004, when he suffered a broken jaw and lost on a decision against Venezuela's Lorenzo Parra.
"I got a taste of fighting on the world stage and that gave me confidence," said Sakata.
Sakata's Kyoei Boxing Gym chief Keiichiro Kanehira said, "I have to respect his decision. He is a wonderful human being. I am thinking he could take over the gym in the future if that is what he wants."