The Korean anime film Yeon no Tegami has revealed its main visual and Japanese-language trailer, along with the full cast for the Japanese dub. The headline announcement is that Yabuki Nako — former member of HKT48 and IZ*ONE — will make her voice-acting debut as the protagonist Sori, while acclaimed voice actor Ono Kensho joins as her classmate Dongseong. Behind-the-scenes dubbing footage and cast comments have also been released.

Story & Origins

The film follows Sori, a girl who has closed herself off from the world, whose fate begins to shift when she transfers to a new school and discovers a letter with no sender. Using the clues inside, she meets new friends and grows — a coming-of-age story woven together by the miracle of letters.

The film is based on the same-titled webtoon by Cho Hyeona, which topped webtoon rankings and became a bestseller in 2018. Director Kim Yongwan previously amassed over 150 million cumulative views with his YouTube short animation series A Day Before Us. Despite this being his feature-length debut, he seamlessly blends nuanced psychological portrayal, beautiful art backgrounds, and poetic visual expression.

Awards & International Success

The film surpassed 220,000 admissions shortly after its Korean release, earning praise as “the best anime of my life” and “a new possibility for Korean animation.” Its theme song “Your Letter,” performed by Lee Suhyun of popular duo AKMU, has been hailed as a new classic of Korean anime music.

At the 26th Bucheon International Animation Festival, the film swept three awards: the Special Jury Prize, the Technical Award, and the Music Award. It has also been well received at the Ottawa International Animation Festival and other international events, with distribution now confirmed in 166 countries and territories worldwide.

Main Visual & Japanese Trailer

The newly unveiled main visual evolves from the teaser’s solitary image into a trio composition featuring Sori, Dongseong, and the mysterious boy Hoyoung. A sun-dappled forest scene and a fantastical night lit by fireflies are combined in a single image, accompanied by the tagline: “This is the story of a miracle that binds us together.”

The visual was produced in a Korea–Japan collaboration, with STUDIO LICO handling layout and key animation, and Comix Wave Films responsible for art backgrounds and photography. The Japanese trailer depicts Sori finding the mysterious letter at her new school and unraveling its secrets alongside Dongseong.

Yabuki Nako’s Dubbing Debut

In an interview following her recording session, Yabuki said she felt a special connection to the project given her idol career in Korea. Initially she had aimed to deliver clean, professional-sounding vocals, but after staff advised her to “just speak naturally,” she found she could relax and perform as herself. She added: “In an age where social media dominates, I hope this film inspires more people to connect through letters. It’ll make you laugh and cry — I want as many people as possible to see it.”

It was also revealed that Yabuki observed Ono Kensho’s entire recording session from start to finish. Ono was so impressed by her performance that he praised her as “truly serious” and asked, “Is this really your first time?” He described his character Dongseong as someone who initially seems blunt, but whose kindness and loyalty to friends gradually comes to light as the story unfolds.

Comments from the Cast & Director

Yabuki Nako: “Having done idol activities in Korea, getting to voice-act in a Korean anime for the first time is something I’m truly happy about — I feel a real sense of connection. Sori shares parts of herself that resonate with me, and I’m glad my first role was her. It’s a wonderful work that makes you laugh and cry, and that anyone can relate to. Please do watch it!”

Ono Kensho: “This is my first time appearing in a Korean anime. I’ve noticed more anime based on Korean comics lately, and I watch a lot of Korean dramas and films myself, so I was genuinely excited when this offer came. I hope the film gives everyone who watches it a chance to think about the important people in their own lives.”

Director Kim Yongwan: “I’ve been listening to Yabuki Nako’s music since her days active in Korea and have always been captivated by her voice. When I first heard her voice sample for Sori, she expressed Sori’s freshness and delicate sensibility so perfectly that I was immediately convinced — ‘This is Sori.’ Ono Kensho is a voice actor with a huge following in Korea, and I’m a fan myself. I feel deeply honoured to have both of them bring this film to life.”

Film Details

• Director: Kim Yongwan
• Original Work: Cho Hyeona — Yeon no Tegami (LINE Manga)
• Japanese Voice Cast: Sori — Yabuki Nako / Dongseong — Ono Kensho
• Production: STUDIO LICO, STUDIO N
• Distribution: Comix Wave Films / KeyHolder Pictures (distribution support)
• Runtime: 97 min | Colour | 5.1ch | 2025
• Japanese Release Date: 25 September 2025

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