|Directed by||Shunji Iwai|
|Produced by||Shinya Kawai|
|Written by||Shunji Iwai|
|Music by||Takeshi Kobayashi|
|Distributed by||Kadokawa Herald|
The film is set in Tokyo at an unspecified point in the near future when the Japanese yen has become the strongest currency in the world. This attracts an influx of immigrants, legal and illegal, to work in the city. The immigrants give the city the nickname Yen Town (円都 en to). The Japanese natives, however, despise the nickname, and in retribution call the immigrants by the homophone Yen Thieves (円盗 en tou), anglicised as "Yentowns" in the film's English subtitles. 
The story centers around a sixteen-year-old girl (Ito) whose mother has just died. The girl is passed on from person to person until she is taken in by a Chinese Yentown prostitute named Glico (Chara), who names her Ageha (Japanese for swallowtail). Under Glico's care, Ageha starts a new life.
The immigrant characters, who speak Japanese, English, Mandarin, or Cantonese, earn their living by committing petty crimes and engaging in prostitution. Ageha does not participate in any of these activities, but is protected by Glico and the other immigrants. The film does not make clear whether Ageha is Japanese or an Asian immigrant.
Eventually, due to a sudden twist of fate, the immigrants are given a chance to realize their various dreams. But in doing so, they destroy their solidarity, and have to face their problems separately.
- Hiroshi Mikami as Fei Hong
- Chara as Glico
- Ayumi Ito as Ageha
- Yōsuke Eguchi as Ryo Ranki
- Andy Hui as Mao Fu
- Atsuro Watabe as Ran
- Tomoko Yamaguchi as Shen Mei
- Nene Otsuka as Reiko
- Kaori Momoi as Suzukino
- Tadanobu Asano as Customer in club
- 1997 Japanese Academy Awards - Newcomer of the Year (Ayumi Ito)
- 1997 Japanese Academy Awards - Most Popular Film
- 1998 Fant-Asia Film Festival - Best Asian Film
Swallowtail Butterfly was also nominated for but did not win the following awards:
- 1997 Japanese Academy Awards - Best Actress (Chara)
- 1997 Japanese Academy Awards - Best Art Direction (Yohei Taneda)
- 1997 Japanese Academy Awards - Best Cinematography (Noboru Shinoda)
- 1997 Japanese Academy Awards - Best Film
- 1997 Japanese Academy Awards - Best Lighting (Yūki Nakamura)
- 1997 Japanese Academy Awards - Best Sound (Osamu Takizawa)
- 1997 Japanese Academy Awards - Best Supporting Actress (Ayumi Ito)
- 1997 Moscow Film Festival - Golden St. George Award
- Cazdyn, Eric (2002). The Flash of Capital: Film and Geopolitics in Japan. Durham: Duke University Press. ISBN 0-8223-2912-3.
- "オリコンさん 1996年".
- Yomota, Inuhiko (2003). "Stranger Than Tokyo: Space and Race in Postnational Japanese Cinema". In Jenny Kwok Wah Lau. Multiple Modernities: Cinemas and Popular Media in Transcultural East Asia. Philadelphia: Temple University Press. ISBN 1-56639-985-8.
- "20th Moscow International Film Festival (1997)". MIFF. Archived from the original on 2013-03-22. Retrieved 2013-03-22.