After graduating from high school, he saved money to make films by working as a construction worker and a truck driver, using his childhood friends as actors. For three years, using an 8mm camera, he spent his weekends making his first film, Above the Clouds, which was released independently in 2003. With the 1,500,000 yen he won from an award for this film, together with Toranosuke Aizawa he wrote Off Highway 20 (2007), which was shot using 16mm film. In 2008, he decided to make Saudade with the help of his childhood friends once again, basing the story in his hometown of Kofu, a city to which many Japanese-Brazilians have moved back from Brazil. Saudade was funded with help from the citizens of Kofu; it took a year and half to film, and was finished in 2011. Tomita submitted this film to international film festivals; it was invited to the Locarno International Film Festival and won the Golden Montgolfière Award at the Festival des 3 Continents in France. The film was invited to many other festivals, including four that organised retrospectives of Tomita’s work, notably the Jeonju International Film Festival. In Japan, the film was viewed by 30,000 people, making it a box office hit. In 2012, Tomita started going back and forth between Bangkok and Tokyo in preparation for his next film, Bangkok Nites.

Filmography