Signal (Japanese: シグナル, Hepburn: Shigunaru), also known as Signal: Long-Term Unsolved Case Investigation Team (Japanese: シグナル 長期未解決事件捜査班, Hepburn: Shigunaru: Chōki Mikaiketsu Jiken Sōsahan), is a Japanese police procedural television series starring Kentaro Sakaguchi, Michiko Kichise and Kazuki Kitamura.

It is a remake of the South Korean drama of the same name written by Kim Eun-hee and aired every Tuesday at 21:00 JST from April 10 to June 12, 2018, on Fuji TV.

[3] Boy group BTS from South Korea sang the opening theme song of the series entitled "Don't Leave Me".

[7] A sequel film, simply titled Signal the Movie, was released in Japan on April 2, 2021.

The film was directed by Hajime Hashimoto [ja], co-written by Kōsuke Nishi and Hiroshi Hayashi, and distributed by Toho, with cast members from the television series reprising their respective roles.