Yabuki (20-4, 18 KOs) kicked off his 2026 after logging a final-round knockout win over Felix Alvarado in December and was largely in cruise control.

The Ring's No. 2-rated flyweight could afford to be after a purposeful start and will surely seek title unifications at 112 pounds against other divisional champions or make another move up in weight, having seen his six-fight stoppage streak end against a Mexican challenger second best but who wouldn't stop trying to turn the tide.

Judges Nobuto Ikheara and Cherdchai Srirat scored it 118-108, while Carl Zappia gave the visitor more grace with a 116-110 scorecard.

The champion exploded into action without warning, landing a pair of equilibrium-shaking knockdowns to assert himself as the aggressor against a tentative Calixto (24-2-1, 10 KOs). A triumphant fist pump heading back to the corner, overlooking fans in his fourth consecutive appearance at Aichi Sky Expo, spoke volumes between rounds.

This title defense could've been over relatively sharpish, though Calixto boxed well behind his jab in round two, despite conceding speed and momentum to a man stringing together two and three-punch combos without telegraphing entries, nor really exerting himself.

Yabuki curled a hook to the body which visibly hurt Calixto, a minute into round four, though the challenger fired back through the fire when it would've been easy to shell up and evade danger. It wasn't immediately obvious but that sequence prompted his best frame of the fight in the fifth. A pair of stinging right hands pinged the champion back against the ropes, while Calixto looked to counterpunch with successful spells in round six.

Yabuki was more sprightly in the seventh and used that impetus in the eighth, hurting Calixto with an overhand right and left hook as the challenger's low defensive guard came unstuck at close-range. Facial bruising didn't stop the 31-year-old trudging forward into more punishment, Yabuki almost leaving him frozen as he landed a combination in the final minute of a nervy ninth.

Calixto's infrequent success kept him competitive in a fight he was miles behind on the scorecards, despite winning some middle rounds, so he needed urgency and connected well in the latter stages. Doing so left him defensively open to counters though, with Yabuki unloading a furious flurry looking mightily close to a stoppage.

Having survived that spell, the champion's combinations continued to land flush but he wasn't having it all his own way as they traded hooks with both wanting to have the final say in exchanges. Into the final frame they went, Calixto swinging for the fences and Yabuki retreating towards the ropes knowing he was well ahead but fatigued.

Unable to keep the Mexican off him, Yabuki remained defensively responsible while overhand rights bounced off his head, uppercuts through the guard and punishing hooks too, before he returned the favor in the final seconds.

Calixto refused to relent after a disastrous first frame, though Yabuki built up an early lead and despite absorbing more damage than he would've liked, proved a worthy winner.

In the chief support bout, John Riel Casimero (36-5-1, 25 KOs) scored a stunning fourth-round stoppage of Luis Nery (37-3, 28 KOs). Former two-weight world champion Nery, who came in 3.2 pounds overweight on Friday, was noticeably a step slow to throw and defensively ragged from the off, as the Filipino fighter took full advantage early to stun him with three first-round knockdowns.

The dominance continued as time wore on, the older man logging a knockdown apiece in rounds two and three set the tone for a dominant display, despite Nery insisting to referee nobuto Ikehara he was okay to continue, though 'Pantera' was folded onto the canvas by a looping left hand in the fourth to end an unforgiving onslaught.