"Ultramarine") is a Japanese manga series written and illustrated by Ching Nakamura [ja].

A live-action film adaptation produced by Netflix, titled Ride or Die, premiered worldwide in April 2021.

[7][5] The manga resumed publication in Monthly Ikki on February 25, 2010,[5][8] and finished on January 25, 2012.

[11] In October 2020, it was announced that Netflix was developing a live-action film adaptation of the manga, titled Ride or Die (彼女, Kanojo, "Her"), which premiered simultaneously worldwide on April 15, 2021.

The film was directed by Ryūichi Hiroki, Nami Sakkawa wrote the scripts and Haruomi Hosono performed the theme song.