Since the 2016 release of the global megahit “Your Name,” the stirring music in the animated epics of the Japanese director Makoto Shinkai has become inextricable from their transporting images.

Shinkai’s recent high-stakes melodramas about star-crossed teenage lovers and impending supernatural catastrophes move to the up-tempo songs and luminous instrumental tracks of the Japanese rock band Radwimps. On multiple occasions, the band’s compositions have also persuaded the filmmaker to make significant changes to his narratives.

In U.S. theaters Friday, “Suzume,” a fantastical saga inspired by the 2011 Tohoku earthquake, represents the third collaboration between the acclaimed storyteller and the musicians.

The international popularity of Shinkai’s films has in turn broadened Radwimps’ audience to include fans beyond Japan’s borders. The band will kick off its first North American tour this weekend in San Jose, Calif.

“Radwimps and I are two wheels of the same bicycle,” Shinkai, 50, said via an interpreter at a hotel in West Hollywood, Calif. “We need each other, and we are pushing one another forward.”

Before enlisting Radwimps, Shinkai had worked with the composer Tenmon, a colleague from his time in video games, on the scores for his short films and early features.

But on the more ambitious “Your Name,” a body-swap tale about a boy and a girl connected through time and space, Shinkai sought to differentiate himself from the influential anime production company Studio Ghibli, and from its co-founder, Hayao Miyazaki, in particular. Over the years, as Shinkai’s profile grew, the director said, journalists continually described him as “the next Miyazaki coming out of Japan.” Despite his unabashed admiration for the master animator, Shinkai disliked the constant comparisons.

“For ‘Your Name,’ I wanted to do something Miyazaki would never do in one of his films, which was use rock music,” he said.

When Shinkai, who had been a Radwimps fan for years, first approached the band in 2014, the artists had been playing together for over a decade but had yet to create music for movies. The lead singer and songwriter, Yojiro Noda, 37, saw this as a chance to reinvigorate the band and push its artistic boundaries while he learned new skills like orchestration.

Upon reading the screenplay, Noda quickly turned around the songs “ZenZenZense” (“Past Past Life”), which became the propulsive soundtrack for the opening sequence, and the power ballad “Sparkle.”

“When I get the script, it’s like a ritual for me to write a few songs just right away without filter and without overthinking it,” Noda, speaking during a recent video interview from Tokyo, explained through a translator.

From ages 6 to 10, Noda lived in the United States, and while his English vocabulary during that time was limited, two words stuck with him: “rad,” to describe something exciting, and “wimp,” with its negative connotation. Putting them together created an oxymoron that he thought fit his band, which he started with middle-school friends in the early 2000s.

Radwimps has gone through multiple configurations over the years, with some members departing or going on hiatus. Its current lineup is Noda, who also plays guitar and piano; the bassist Yusuke Takeda; and the drummer Satoshi Yamaguchi.

Once Noda decides on the melody and lyrical theme based on Shinkai’s text, he shares it with his bandmates, who enrich the sound with their instruments, synthesizers and percussion.

The beautifully hyperbolic lyrics, however, are all Noda’s. “He’s one of the very few poets left in Japan right now who can write the way he does,” Shinkai said.

The composer, who’s also written and performed English-language versions of some of the songs created for Shinkai’s animated romances, explained: “All of the music for ‘Your Name’ came from that longing to see each other that was so genuine and pure between the two characters, Mitsuha and Taki.”

The “Your Name” soundtrack album debuted at No. 1 on the Japanese national album chart and stayed there for another week. That distinction came on top of the monumental box-office success that eventually turned the film into the third-highest-grossing Japanese production in the country’s history, animated or otherwise.

“Radwimps’ music was essential to the success of ‘Your Name,’” Shinkai said. “It really propelled that film into a worldwide social phenomenon.”

For Shinkai, Noda’s interpretation of his stories “feels like his way of giving me feedback on my screenplay, but it just happens to come in the form of music.” These exchanges, he believes, have become essential for him to see the full potential of what the film can be.

On their second outing together, “Weathering With You” (2020), in which a young man must choose between love and saving Tokyo from torrential rain, Shinkai decided to expand a pivotal sequence where the protagonists fall from the sky after he listened to the choir voices featured in “Grand Escape,” one of the early songs Radwimps produced for the movie.

Something similar occurred with “Suzume.” Noda delivered “Tamaki,” a song about the aunt and guardian of the 17-year-old title character. Inspired by the tune, Shinkai realized Tamaki’s relevance and added more interactions between her and Suzume. Such changes can be made because the band comes on board long before the visual development starts.

For the theme song, “Suzume no Tojimari” (also the name of the film in Japan, where it’s already a hit), Noda listened to Shinkai’s suggestion that the music should capture the scent of the earth itself and the sound of the wind.

They also agreed that since a girl is at the center of this whimsical coming-of-age saga, the track needed a female singer. After scouring multiple social media platforms for the right voice, they came across a TikToker named Toaka. She had no professional experience, but videos of her singing at home impressed them.

Radwimps has now received three Japan Academy Awards — the country’s Oscar equivalents — for best music, one for each of their collaborations with Shinkai. (For “Suzume,” they shared the prize with composer Kazuma Jinnouchi, who created some of the score’s instrumental moments.)

With no plans for the partnership to end, Noda thanks destiny, a concept crucial to the director’s metaphysical adventures, for bringing them together.

“Shinkai often tells me there’s no limit to creativity,” Noda said. “He’s an inspiration, and writing songs for his anime is always going to be something special for me.”