Yamanaka's most recent defence came against Belgium's former European champion Stephane Jamoye and the Japanese fighter really did as he pleased dominating a usually tough fighter who was dropped 4 times before eventually being stopped in round 9.
The performance, whilst great on paper, did in a way make Yamanaka look like a 1-trick pony at times. Time and time again he was lining up his thunderous left hand though at the end of the day he was using it to great effect and it seemed that almost every time he landed he was hurting the visiting fighter who was unable to adapt. The fact Jamoye couldn't change his game plan, at all, allowed Yamanaka to do what he was doing. It is worth noting however that when pushed in other fights Yamanaka has shown an ability to adapt.
We are awaiting to hear who Yamanaka will be defending his belt against next time out though it seems he will be back in October to defend against a highly ranked challenger. Hopefully that bout will be more compelling than this one which was simply too one sided.
(Video thanks to LysAlexandrov)