Kazuto Ioka defeated Argentina's Roberto Domingo Sosa to successfully defend his WBA flyweight title for the first time with a unanimous decision on Sunday.
At Osaka's Edion Arena, the 26-year-old Ioka outpointed his 10th-ranked, 30-year-old opponent in a 12-round tactical skirmish in which both men avoided prolonged exchanges.
"I wanted a knockout, but I'm glad to get the win. Today's my grandmother's birthday and I'd like to dedicate this win to her," Ioka said in the ring before introducing his grandmother to the crowd.
The judges scored the fight 119-109, 120-108, 119-109 as Ioka improved to 18-1 with 10 wins by knockout, while Sosa's record fell to 26-2.
Earlier, Katsunari Takayama defeated compatriot Ryuji Hara by technical knockout in the eighth round in the second defense of his IBF minimumweight championship.
The two men pounded away from the start, and though the 32-year-old Takayama was caught flat-footed a few times and was bleeding from a cut on his forehead, he began to dominate the bout.
"It's a relief to have won," Takayama said. "I've been cut so many times in the past, I knew what to do about it."
When the eighth round opened, Takayama went straight to Hara's body. When his opponent began to stagger, Takayama pummeled Hara's head until the referee stopped the fight at 1 minute, 20 seconds.
"He was tough and powerful," Hara said. "He had a good rhythm with his punches and I wanted to move more but that right hand finished it."
Takayama improved to 30-7 with one draw and 12 wins by knockout. Hara, who was taking his first shot at a world title, fell to 19-2 with 11 wins by knockout.