The 24 year-old improved his unblemished record to 14-0 in what was his seventh straight world title defence as all three judges handed Ioka the win 119-109, 119-110 and 115-113.
On the undercard, Fahlan Sakkreerin Jr stunned former world 105lb champion Ryo Miyazaki with a third round knockout. The Thai puncher inflicted a first defeat on the home fighter to end any hopes of an immediate title shot at 108lbs in early 2014 after question marks were raised about Miyazaki safely making the weight seemed justified.
In Ota-City, Takashi Uchiyama made the eighth defence of his WBA super-featherweight belt despite being put on the canvas by compatriot Daiki Kaneko in the tenth round of their clash.
The experienced champion, 34, remains undefeated through 22 contests after the convincing triumph as all three ringside officials came back with scores of 117-110 in the night’s main event.
The chief support bout saw Takashi Miura keep a firm grip on his WBC version at 130lbs by stopping Dante Jardon in nine rounds – meaning a unification with Uchiyama could be in offing in 2014.
Also on the bill, ex-world title holder Kohei Kono warmed up for his upcoming bid to regain the WBA super-flyweight title with a straightforward three-round win over debutant Daut Manopkanchang, whilst Mexican Carlos Cuadras easily improved to 29-0 with the 24th knockout of his career.
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Pictures by Sumio Yamada
