This is a decent fight between two young Japanese Flyweights. Yamauchi is 7-1 with his only defeat coming to former world title challenger Wulan Tuolehazi on the road in China.
Yamauchi is a proficient body puncher with decent boxing skills to back up his aggressiveness. He has a good chin and is only improving the more fights he has.
Yuta Nakayama is 8-3-1 with five knockouts and has faced a decent level of competition domestically. I think Nakayama isn’t as good technically as Yamauchi and doesn’t have his style of body punching. His defence is also questionable at times.
I think Ryota Yamauchi will win by knockout within six or seven rounds due to his aggressive body punching style. I don’t think Nakayama has the power or stamina to keep Yamauchi off him for twelve rounds.