The fight in question saw Amagasa defending his OPBF title by 8th round TKO over Thailand's Maxsaisai Sithsaithong (14-5, 3).
Unfortunately the lack of knowledge about Sithsaithong saw Amagasa only sparring with right handed fighters, a major issue given that the Thai was a southpaw, something that Boxrec.com still need to correct. Typically when fighting against a southpaw a fighter has particular focus in sparring on getting used to the stance of a southpaw. Amagasa, thinking that Sithsaithong was an orthodox fighter, didn't think about preparing for a southpaw.
It's fair to say that had Amagasa known he was fighting a "lefty" he'd have sparred with several and been more prepared. Had he been more prepared we believe he'd have put on a much better performance than this disappointing one that looked disjointed and messy.
(Image courtesy of boxingnews.jp, in it we see the Thai fighting from the Southpaw stance)