Birthright (臍帯, Saitai, "Umbilical Cord") is a 2010 Japanese horror film directed, produced, and co-written by Naoki Hashimoto. The film involves a young woman named Mika (Sayoko Oho) who watches the married couple, Minoru Takeda (Hiroshi Sakuma) and his wife Ryoko (Ryoko Takizawa) and their teenage daughter Ayano (Miyu Yagyu) from outside their home. Mika approaches Ayano and says she knows a male student who would like to meet her. Ayano accompanies her only to find that this is all part of Mika's plan to get revenge on her birth mother.

The film premiered at the Tokyo International Film Festival in 2010. It received a theatrical release in Japan in April 2012.