At the time neither man was a big name, in fact if anything Iwasa was the slightly bigger name with some in Japan tipping him as a potential star though Yamanaka was world ranked by the WBC and WBA at the time. This bout was Yamanaka's first defence but it was supposed to be Iwasa's coming out party and the fight that allowed him to announce himself as a legitimate future champion. What we ended up getting however was a bout that help both men increase their standing in the sport whilst also seeing Yamanaka defend his belt to remain unbeaten.
The fight started somehwat slowly with both trying to establish their jabs in the opening minute or so. From then on however it became a fast paced but highly skilled war with the two men unloading when openings arose, and there was plenty of openings. The action and power of both men seemed to take it's toll at various points with Yamanaka notable shaken in round 2 and Iwasa coming apart late in the bout as he began to tire out.
Despite the loss for the then 21 year old Iwasa he still impressed showing good skills, a lot of heart and real fighting spirit, all things that helped "Eagle Eye" win over fans. For Yamanaka this win helped boost him up the world rankings and in his very next fight he would go on to stop Christian Esquivel for the WBC world title, a title he still holds today. As for Iwasa he would go on to win both the Japanese and OPBF titles and the general view is that he will go on to claim a world title at some point.
(Video courtesy of Gyuzen Meet the Meat Channel)