The musical drama Glass Heart has launched on the Netflix platform. The series follows Akane Saijo, a university student and aspiring drummer who is recruited by musician Naoki Fujitani for his new band. The show is an adaptation of the novel series by Mio Wakagi, which began its serialization in 1993. The production involved large-scale concert sequences and extensive musical training for its cast.
The production of Glass Heart was a large-scale undertaking, described in production materials as one of the largest in the history of Japanese drama. The project was developed for a global audience, following a trend of international distribution for television series from various countries. Lead actor Takeru Satoh also serves as a co-executive producer. Satoh was involved in casting, approaching his co-stars for their roles. The production required over a year of instrumental training for the main actors and used thousands of extras for its concert scenes.
A Narrative of Artistic Genesis and Modernized Themes
The narrative of Glass Heart begins when Akane Saijo, a university drummer, is dismissed from her band because of her gender. She is then scouted by Naoki Fujitani, a musician known as the “Amadeus of Rock”. Akane joins Fujitani’s new band, TENBLANK, alongside guitarist Sho Takaoka and pianist Kazushi Sakamoto. The series follows the band’s development, from recording sessions to television appearances and arena concerts. A rival band, OVER CHROME, led by vocalist Toya Shinzaki, provides a source of external conflict. The series explores themes of artistic collaboration, the creative process, and music as a form of personal expression. A central theme is gender dynamics in the music industry, initiated by Akane’s dismissal from her original band.
The source material, Mio Wakagi’s novel, was first published in 1993. The adaptation’s screenwriting team is composed of four women: Mari Okada, Tomoko Akutsu, Shiho Kosaka, and Anna Kawahara. Mari Okada, the lead writer, is known for her work in the anime industry on series such as Toradora! and Anohana: The Flower We Saw That Day, which often explore psychologically complex characters and themes of trauma and social anxiety. Her writing frequently draws from personal experience. The selection of this writing team provides a contemporary perspective on the novel’s 1993 premise, which is described as a “timeless masterpiece”.
An Ensemble Cast and a Narrative of Performance
The cast includes several prominent Japanese actors. Takeru Satoh, who plays musician Naoki Fujitani, has a background in projects such as the Rurouni Kenshin films and the drama First Love. Satoh is also a co-executive producer on the series. The protagonist, Akane Saijo, is portrayed by Yu Miyazaki, a voice actor known for roles in anime series like A Sign of Affection and The Heike Story, in her first major live-action role. Miyazaki was chosen for the part through an audition process. The other members of the band TENBLANK are played by Keita Machida (Alice in Borderland, Cherry Magic!) as guitarist Sho Takaoka, and Jun Shison (Ressha Sentai ToQger, YuYu Hakusho) as pianist Kazushi Sakamoto. The rival vocalist, Toya Shinzaki, is played by Masaki Suda, whose credits include Kamen Rider W and a voice role in The Boy and the Heron. The supporting cast includes Erika Karata, Akari Takaishi, Pistol Takehara, and YOU.
The principal actors spent over a year learning to play their characters’ instruments for the performance sequences, with the production describing the process as the cast making their “actual debut as a band”. The casting of Miyazaki, a relative newcomer to live-action lead roles, alongside established actors reflects the story’s plot of an amateur musician joining a group of experienced artists.
A Director’s Vision and the Language of Cinematography
The series is directed by Kensaku Kakimoto and Kotaro Goto, with Kakimoto also serving as the primary cinematographer. Kakimoto’s background includes work in art photography, commercials, and music videos. His filmography includes the feature Parasite in Love and the documentary LIGHT UP NIPPON. The series’ cinematography uses different styles for its musical and dramatic scenes. The live performance sequences are filmed in the style of concert films, using “rapid cuts, dramatic zooms, sweeping drone shots, and slow motion” to convey the “electrifying energy” of a live event. This approach also highlights the physical demands of musical performance. In contrast, the non-musical scenes are filmed to create a “dreamy, soothing atmosphere” using specific framing and “spatially aware lighting”. The lighting design is by Tetsu Moritera and the production design is by Ryo Nobuka. Kakimoto’s dual role as director and cinematographer provides a unified visual approach to the series, applying his visual style to a large-scale drama production.
The Sonic Architecture: A Convergence of Musical Artists
Music is a central element of Glass Heart‘s narrative. The original score is by Masakatsu Takagi, a composer and visual artist known for his work on the films of director Mamoru Hosoda, including Wolf Children, The Boy and the Beast, and Mirai. Takagi’s compositions often blend piano, ambient textures, and electronic elements with sounds from the natural world. The series also features a soundtrack of original songs from a “stellar lineup of leading musicians from Japan’s current music scene,” with a total of 26 contributing artists overseen by music producer Katsuya Yamada. Yojiro Noda of the band RADWIMPS wrote and composed the title track, “Glass Heart,” performed by Takeru Satoh, and another song, “Crystalline Echo”. Other contributors include Taka from ONE OK ROCK and Yohei Kawakami from [Alexandros], as well as producers and artists like Ryujin Kiyoshi, Yaffle, and TeddyLoid. These songs are performed by the fictional bands TENBLANK and OVER CHROME within the story, and their lyrics and music are used to advance the plot and character development. The project brings together Takagi and Noda, two composers known for their work on commercially successful and critically noted anime films. Their involvement provides a specific musical identity for the series, similar to the role music plays in contemporary Japanese animated features.
A Synthesis of Production Elements
Glass Heart is a television production based on a long-running novel series by Mio Wakagi. The adaptation was developed for a global audience and features a cast of well-known Japanese actors who underwent extensive musical training for their roles. The creative team includes lead writer Mari Okada, known for her work in anime; director and cinematographer Kensaku Kakimoto, who brings a background in visual arts to the project; and a musical team led by composer Masakatsu Takagi and featuring songs from Yojiro Noda and other Japanese artists. The production was executed on a large scale, involving complex concert sequences.
The eight-episode series Glass Heart was released for worldwide streaming on Netflix on July 31, 2025.
