The quickest of those 6 defences came in his second bout as champion as he battled first time title challenger Kota Koike. Interestingly it was the third bout between the two men who first met in 2005 with Kato taking a 4 round decision and again in 2007 when Kato took an 8 round decision. Through the 12 rounds of their first two bouts together neither man had managed to stop the other, and from looking at the scorecard neither man had even managed to score a knockdown.
With their history together most fight fans expected this to go the distance surprisingly it lasted less than a round with Kato hurting his challenger early and then going for the kill, eventually forcing the referee to save Koike.
Sadly for Koike this loss started his downfall in boxing and he'd fight only twice more, losing both of those bouts. For Kato however it was a win that he has built on brilliantly on.
Several things worth noting about this bout are that this was only Kato's 3rd opening round stoppage, his first sine 2005. It was also the 4th stoppage loss of Koike's career though two of those previous stoppages had come to Daiki Kaneko and Shinya Iwabuchi, both of whom became national champions themselves!
(Video courtesy of kadoebiebi)