
i kinda don't understand. why tokyo have 3 but miyagi (karasuno prefecture) only 1?

It's because there are waaay more high schools in Tokyo. So it's decided not just by prefecture, but by population as well.

The larger prefectures with significantly more teams like Tokyo and Hokkaido get 2 representatives. Also, the prefecture hosting the Nationals always gets a 'host representative' which is why Tokyo has three.
this father and child not giving any cuteness that usually i find in yaoi with child. and the father too dumb too about child. well i think if u life with child u'll know about the child. and the child also annoying, more like midle scholer.
ah well... but i give apreciate for mangaka for the work.