General · EdgepediaOctober 3, 20265 min read

Sky of Love

Sky of Love (恋空, Koizora) is a 2007 Japanese romantic drama film directed by Natsuki Imai, adapted from Mika's mobile phone novel Koizora: Setsunai Koi Monogatari (恋空～切ナイ恋物語～), a story the author wrote from her own experience. It stars Yui Aragaki as high school student Mika and Haruma Miura as Hiro, and it became one of the defining hits of the Japanese mobile-novel adaptation boom, earning about 3.9 billion yen at the box office.¹^•²

Key fact	Detail
Release	November 3, 2007, Toho; 129 minutes, color, 35 mm¹
Director	Natsuki Imai, a TBS drama director ("Orange Days"), for whom this was a feature film debut³
Source	Mika's mobile novel, serialized on the Maho no i-rando site from December 2005, ranked first on the site for six months⁴
Book sales	Published by Startts Publishing in October 2006 in two volumes; passed one million copies within one month of release⁴
Cast	Yui Aragaki (Mika Tahara), Haruma Miura (Hiro / Hiroki Sakurai), Keisuke Koide (Yu Fukahara)¹
Box office	About 3.9 billion yen, 6th place in the 2007 Japanese film ranking²
Music	Theme song "Tabidachi no Uta" by Mr.Children; insert song "heavenly days" sung by Yui Aragaki⁵

Spoilers

Plot

Mika, a first-year high school student, loses her cellphone and finds it in the school library; afterward an unknown caller phones her daily through the summer. When school resumes she meets the caller: Hiro, a bleached-haired classmate with a delinquent manner who proves his identity with a photo of the sky on his phone. The two fall into her first love.⁸^•⁹

The relationship is tested by a series of ordeals. Hiro's ex-girlfriend Saki harasses Mika at school and beyond, and lures her into an assault by men; Mika becomes pregnant and miscarries after further violence from Saki. Hiro, deciding to become a father, asks Mika's parents for marriage, but the miscarriage follows.⁷^•²

Hiro then abruptly breaks off the relationship without explanation. Mika, wounded, begins dating Yu, a gentle university student who is Hiro's opposite in temperament, and slowly recovers. She then learns the truth: Hiro is dying of an illness, and he had left her so that she would not grieve. Mika breaks up with Yu and returns to Hiro, and the two reaffirm their love as he fights the disease.¹^•¹⁰

The source novel

The film draws on a phenomenon of mid-2000s Japanese publishing: the keitai shosetsu, or mobile phone novel, written and read on handsets. Mika, an office worker with no prior writing experience, began serializing Koizora on the free homepage service Maho no i-rando in December 2005. The story held the site's number-one popularity ranking for six months and, by eiga.com's April 2007 report, had drawn more than 12 million cumulative readers; Cinema Today later put the figure at 16 million readers, and the Japan Film Database records more than 20 million hits, so the audience counts vary by how they were measured.⁴^•⁶^•¹

In October 2006 Startts Publishing brought out the story as a two-volume book, Koizora / Setsunai Koi Monogatari, which passed one million copies in a single month; KINENOTE gives total sales of 1.4 million copies. The novel is credited with helping fix the mobile-novel boom among female middle and high school students.⁴^•⁷^•³

Production and release

Natsuki Imai, known for directing TBS dramas including "Orange Days" and "Taiyo no Uta," made his theatrical debut with this film. The screenplay is by Mutsuki Watanabe, with cinematography by Hideo Yamamoto and music by Shin Kono. Production companies included TBS, Maho no i-rando, LesPros Entertainment, Toho, MBS, TC Entertainment, and Fine Entertainment, under the "Sky of Love" Production Committee; Toho distributed.³^•⁵^•¹

Principal photography took place mainly in Oita Prefecture. The film was screened as a special invitation entry at the 20th Tokyo International Film Festival on October 23, 2007, where Toho staged a heart-shaped sky drawing over Roppongi with an aircraft; clouds parted in time for the photo session.¹¹^•⁶

For Aragaki, whose previous lead role was in Koizora's lighter contemporary Koi suru Madori, the role involved material new to her image, including pregnancy and miscarriage; she said she felt pressure and anxiety but would do her best. It was her second lead film.⁴^•²

Reception and related media

The film earned about 3.9 billion yen, a substantial hit for a Japanese film, and WOWOW places it 6th in the 2007 domestic box-office ranking. Audience response was sharply divided: Filmarks users give it 3.2 of 5 across about 79,000 reviews, allcinema users 3.5 of 5, while Yahoo's aggregate sits at 2.3 with half of voters giving one star. It also ranked 2nd in that year's Bunshun Kiigo Prize, an award selecting the year's worst films.²^•¹²^•³^•¹¹

The franchise expanded quickly. A side story told from Hiro's viewpoint, Kimi Sora (君空), was published in late October 2007. A manga adaptation by Ibuki Haneda ran in Futabasha's COMIC Maho no i-rando in four volumes, and a soundtrack appeared on Harbor Records on October 31, 2007. A television drama adaptation was broadcast on the TBS network in August 2008, airing Saturdays at 7:58 pm.¹¹^•¹³

Scholarly commentary has read the film through the aesthetic of mono no aware (Japanese aesthetic of gentle sorrow at life's impermanence): the sky serves as a metaphor for love and memory, and Hiro's terminal illness keeps the impermanence of life in view, turning the sky into a symbol of a love that continues beyond his physical existence.¹⁴

References

Initially written Oct 3, 2026 · Reviewed: Oct 3, 2026; Oct 25, 2026 · Edited: Oct 3, 2026; Oct 21, 2026; Oct 25, 2026; Nov 1, 2026