What follows is a mentorship montage 180 degrees removed from “The Karate Kid” or any number of conventional kung-fu character reinventions: Kumatetsu proves to be a disastrous teacher, losing his temper at the slightest provocation, while Kyuta actually manages to outsmart his mentor, getting the better of the cranky old bear in a series of amusing scenes that compress eight years of rigorous training and personal evolution into a rowdy bonding experience.
Hosoda, who was briefly and ill-fatedly connected with Miyazaki's Studio Ghibli a decade ago before branching out with his own organization, delivers a raucously entertaining if slightly overlong romp which borrows liberally from existing sources — it's at heart a Harry Potter-flavored fusion of The Jungle Book and The Karate Kid — but has more than enough character and brio to stand foursquare on its own two hairy feet.