Yukinori Oguni stunned Jonathan Guzman to rip away the IBF super-bantamweight title At the Shimazu Arena in Kyoto.
The unheralded 28 year-old, who was largely anonymous before the fight, upset the tough Dominican 115-112 on all three cards.
In the co-feature, WBA Flyweight champion Kazuto Ioka kept his belt with a seventh round stoppage of Stamp Kiatniwat.
Earlier, super-flyweight Sho Ishida made it 23-0 in the paid ranks when dispatching Petchnamnung Srisaketpattana in two.
WBN’s Young Fighter of the Year for 2015, Kosei Tanaka became a two-weight world champion in just his eighth fight when stopping Moises Fuentes at the Memorial Center in Gifu.
The 21 year-old, who claimed the minimumweight version in pro fight number five last May, continued his rise through the divisions with a fifth round victory to pick up the WBO light-flyweight belt.
Tanaka has now been belatedly added to the nominees for the Young Fighter award the talented puncher was bestowed with last year.
Also on the bill, former world champion Akifumi Shimoda lost out in his bid to land the Japanese featherweight title when out-pointed by Shota Hayashi over ten rounds.
At Ota-City Gym, WBA Light Flyweight title holder Ryoichi Taguchi clung to his belt in a fierce battle with undefeated Carlos Canizales.
Taguchi was awarded the fight 116-112 after twelve rounds, with a second scoring it 116-112 to the 16-0 Venezuelan. The final judge had it 114-114 giving plenty of reason for the pair to be pitted together again in the New Year.
In the main event, Jezreel Corrales defeated Takashi Uchiyama for a second time in eight months via a split decision.
The first meeting ending in a devastating secound round knockout, although this time around Corrales was forced to go the distance.
At the end of the twelve rounds, judges at ringside gave the decision to Corrales 117-110 and 115-112 whilst a third saw it for Uchiyama 114-113.