It's not rectoned it's something that happened in the middle of Miyata's life with his dad. The author Morikawa wants to build deph into why Miyata seeks to perfect his fathers technique. As in the beginning his that was his motivation and there match with Ippo, the one driving Miyata now is not a final match with Ippo, but his fathers legacy of boxing against the son of the man that defeated his father in boxing.
Also read the Sendo Gaiden, it has more than the "like my dad" motivation to be strong.
__________________
Vampire+Sisters
|