Shunji Iwai, Japanese filmmaker.[Photo provided to China Daily]

Iwai, who's known for a series of youth hits, says most of his film plots are rooted in real-life stories.

Fireworks, originally used to ward off evil things, have a long history in Japan and become an integral part of summers in the country.

So, it is not a surprise to see the shapes that fireworks form repeatedly discussed in the movie.

Iwai says that the question about the shape of fireworks in the sky once haunted him, leading him to produce a story to figure out the answer.

Iwai once dreamed of becoming an animator. But most of his acclaimed titles are live-action dramas, and he has only directed one animated movie, The Case of Hana & Alice (2015).

Iwai says, "Compared with live-action dramas, animation work is much more time-consuming since animators paint the characters and scenes piece by piece."

Animators who worked on Fireworks, Should We See It from the Side or the Bottom? spent five years on the film.

Iwai's work will remind Chinese fans of the 1995 romantic film, Love Letter, and the 2001 movie, All About Lily Chouchou.