Takuma Inoue became the new WBC bantamweight world champion with a unanimous points win against Tenshin Nasukawa.
Inoue was awarded a 116-112, 116-112, 117-111 victory over his fellow Japanese fighter after 12 rounds in Tokyo.
The pair had both weighed in at 117.7 pounds to contest the belt vacated by Junto Nakatani, who has moved to super featherweight.
Takuma Inoue was accompanied to the ring by his brother Naoya Inoue, who is the undisputed super bantamweight world champion, and proved a convincing winner on the scorecards of the judges.
There were plenty of fiery exchanges between the two fighters as Inoue improved his record to 21 wins and two losses from 23 outings.
Former kickboxer Nasukawa suffered his first defeat, having won his first seven boxing fights.