URAYASU, Japan South Korean Choi Yo-sam retained his World Boxing Council (WBC) light flyweight title after stopping Japanese challenger Shingo Yamaguchi in the 10th round of their scheduled 12-rounder on Saturday.

Choi, fighting for the first time in more than a year, defended the title he won in October 1999 for the third time on a technical knockout two minutes 18 seconds into round 10.

The 29-year-old Choi recovered from a cautious start to dominate the middle rounds and floored Yamaguchi with a left hook in the ninth.

"I was only at 30 percent because I have been out of the ring for such a long time. That was the only reason the fight lasted until the 10th round," said Choi, who improved his record to 24 wins, including 13 knockouts, and one defeat.

Yamaguchi, seven years younger and taking his first world title shot in only his 15th professional bout, admitted it had been a learning experience, reported Reuters.

"He hit me so hard that I felt the lights were going to go out. I have learnt a lesson and will try to use it to my advantage next time," said Yamaguchi, who left the ring with a record of 11 wins -- five inside the distance -- three losses and one draw.