'Inu-Oh’: A rock musical that won't be headlining anytime soon

It’s a familiar tale: a gifted artist finally gets a big break, only to find their creativity blunted by commercial demands and industry politics. I’m not talking about the medieval pop star protagonist of Masaaki Yuasa’s “Inu-Oh,” but about the film’s director.

The past few years have been the most productive of Yuasa’s career, while yielding some of his least essential work. This anachronistic rock musical promises a return to the playful, literary surrealism of “The Tatami Galaxy” (2010) and its 2017 spin-off, “Night Is Short, Walk On Girl,” but comes up short.

“Inu-Oh” sounds amazing on paper, which may be part of the problem. It features character designs by Taiyo Matsumoto (“Tekkon Kinkreet”) and is based on a 2017 novel by celebrated author Hideo Furukawa, who wrote it on the back of translating the 14th-century epic, “The Tale of the Heike,” into modern Japanese.

The latter was recently adapted as an animated TV series, “The Heike Story,” and “Inu-Oh” assumes that viewers will already be up to speed. (If you aren’t familiar with this saga of warring clans in 12th-century Japan, a quick trip to Wikipedia might be in order.)

The film’s story takes place in the late 1300s, by which point the exploits of the doomed Heike clan have been immortalized in popular song, performed by blind biwa (lute) players. The latest addition to their number is Tomona, who lost his sight — and father — while recovering a cursed imperial sword for the benefit of some noblemen from the capital, and is still nurturing a hefty grudge.

Heading to Kyoto, he befriends the deformed son of a celebrated noh performer, who calls himself Inu-Oh — literally, king of the dogs. Together, they set out to rewrite the popular canon and placate the spirits of fallen Heike warriors whose stories have yet to be told, sticking it to The Man in the process.

Tomona (voiced by Mirai Moriyama) grows his hair long and starts acting as a rock evangelist for Inu-Oh’s bombastic stage routines. And that’s where the film runs into problems.

The opening act is a sensory overload, using a range of animation techniques to capture how the two protagonists experience the world around them. However, having demonstrated how much he can do, Yuasa then devotes huge chunks of screen time to just letting Inu-Oh and his hard-riffing hype man perform.

It’s not so much a rock musical as an animated concert movie, and there isn’t nearly enough variety in the visuals or music to keep things interesting.

The songs, by Otomo Yoshihide, are mainly classic rock with Japanese trimmings, like something Flower Travellin’ Band might have cooked up in the early 1970s. They’re considerably enlivened by the vocal pyrotechnics of Queen Bee singer Avu-chan, who plays Inu-Oh, but even this can’t compensate for Yuasa’s insistence on repeating the same tune multiple times.

That’s not to say it’s a total letdown. The movie contains good insights into how folk traditions are born, and how popular culture — and history itself — are manipulated by those who wield the power in society. There are individual sequences that reach the psychedelic heights of Yuasa’s best work. But too often, this tale of the liberating power of art is about as mind-expanding as an early-afternoon set at Fuji Rock Festival.