Rising actress Miro and B&ZAI member Michiharu Inaba will co-star in the movie “17-sai no Proof” (17歳のプルーフ), which is set to be released in February 2027. Along with the film’s announcement, promotional visuals and comments from the cast and staff have also been unveiled.
Set at a high school overlooking a beautiful inlet, the film quietly portrays the secrets hidden within an old book and the wavering emotions of second-year high school students.
Riko, who has never been in love, and Minato, her childhood friend and a member of the library committee, accidentally discover a book written by a graduate from 30 years earlier. Inside is a confession of guilt stating, “I killed someone with these hands.”
Using clues hidden within the novel, the two begin unraveling the mystery, and in the process, they gradually come to realize feelings within themselves they had never known before.
Miro, who plays Riko, gained attention through Suntory Natural Water Sparkling Lemon commercials and BUMP OF CHICKEN‘s “Gravity” music video. In 2025, she made her film debut as the lead in “White Flowers and Fruits” (“Shiro no Kajitsu” / 白の花実), which was selected for the competition section of the 73rd San Sebastián International Film Festival.
Meanwhile, Inaba, who has been active since 2018 as a Junior (pre-debut) artist through live performances, television appearances, and stage productions and is part of the eight-member group B&ZAI, takes on the kind-hearted role of Minato, marking both his first feature film and co-starring appearance. The picture will see these two fresh new stars bring a natural brilliance and youthful presence to this enigmatic and sincere story.
The film stemmed from the “TSUTAYA CREATORS’ PROGRAM” (TCP), which has discovered numerous original projects—including “The Lies She Loved” (2018), “The Cinderella Addiction” (2021) and “My Daddy” (2021). The screenplay, which began as “Kaze yo Fuke, Bokura no Atsui Namida wo” (Blow, Wind, Our Hot Tears), won the Special Jury Prize in the screenplay category of the 2022 TCP awards. Award recipient Yusuke Ichikawa refined the script, which would ultimately adapted into “17-sai no Proof.” Director Tadaaki Horai, who is known for works centered on youth and romance—such as the TV dramas “My Love Mix-Up!” (2021) and “Minami-kun ga Koibito!?” (2024), as well as the films “Wait a Minute, Baseball Club!” (2018) and “You Guys Are All Annoying!” (2019)—carefully captures the delicate atmosphere and emotional warmth shared between Riko and Minato.
With mystery, secrets, and the fleeting sparkle that exists only in the moment, this motion picture proudly joins the youth genre as a gentle tale crafted through the emotions of rising new stars and highly skilled creators.
Comments from the cast & crew
Miro
“I’m Miro, and I played Riko Nogisa.
Playing Riko allowed me to experience emotions I had never known before, and there were many moments when I felt confused. However, with the support of the cast and crew, I was able to truly face Riko and portray her sincerely. I believe this film conveys the preciousness of caring for someone, along with the wavering emotions, warmth, and sadness that come with it.”
Michiharu Inaba
“I’m Michiharu Inaba from B&ZAI, and I played Minato Shiozaki. This was my first film appearance and also my first starring role, so I remember being so surprised when I heard the news that I was literally speechless. Minato is a kind-hearted boy who observes others carefully and quietly supports them. Through a certain book, he gradually grows alongside Riko and begins to confront his own feelings. I believe audiences of all generations will be able to relate to that journey. These two seventeen-year-olds are still imperfect and awkward, but as they experience many emotions surrounding this one book, they gradually begin moving toward adulthood. I would be happy if viewers could warmly watch over them. Please enjoy the film in theaters.”
Screenwiter Yusuke Ichikawa
“What I wanted to portray were the earnest and pure feelings that we have all, somewhere in our hearts, forgotten over time. The road to adapting this into a film was far from smooth, but the overwhelming passion of the cast and staff breathed an incredibly fresh life into this story. I hope that after watching the film, a clear and gentle breeze will pass through the hearts of the audience in the silence that remains.”
Director Tadaaki Horai
“Together with Miro, Inaba, and our wonderful cast and staff, we carefully wove together the beautiful world created by Ichikawa’s script across many wonderful filming locations. Looking back now, it feels almost like a miracle. I hope that this film, ’17-sai no Proof,’ which was made with so much passion, will be enjoyed by as many people as possible and remain somewhere in their hearts for a long time. Thank you for your support.”