Japanese commercial films nearly always run on the well-worn rails of franchise and formula. Originality in script and concept is gifted to only a chosen few with strong box-office track records — Hayao Miyazaki, Koki Mitani and Shinobu Yaguchi among them. Though not as well-known as the anime master (Miyazaki) and the master self-promoter (Mitani), Yaguchi has reeled off hit after comedy hit over the past decade, including "Water Boys" (2001), "Swing Girls" (2004) and "Happy Flight" (2008).

Though their stories may not follow a single pattern, their heroes typically have to achieve or demonstrate some sort of mastery, be it in synchronized swimming ("Water Boys"), jazz music ("Swing Girls") or flying commercial jets ("Happy Flight"), often starting from zero. Doing so requires teaming up with others and persevering over obstacles with the good old ganbare ("go for it") spirit.

His new comedy, "Robo-G," has all of the above elements, but after nearly four years away from the screen, Yaguchi combines them in new, blackly comic ways that may disappoint fans expecting the fizzy energy and rousing finales of his biggest hits. Can we put it down to more maturity in the director, or in his hero, a 73-year-old jiji (grandfather — and the supplier of the "G" in the title)? In either case, "Robo-G" has a rare freshness of concept, as well as the sort of laugh-out-loud gags fans have come to expect from Yaguchi, though they come thicker and faster in the first half-hour than the last.