Kimi No Shiranai Monogatari by Supercell

"Kimi no Shiranai Monogatari" (lit. "The Story You Don't Know") is a J-pop song by the Japanese band Supercell, written by Ryo. Supercell released it as their debut single in August 2009 by Sony Music. The title track was the ending theme song to the 2009 Bakemonogatari anime series, and the B-side track "Love & Roll" was the theme song for the 2009 Cencoroll anime film. A music video was produced for "Kimi no Shiranai Monogatari", directed by Hirohisa Sasaki.

Lyrically, the song deals with an unrequited love.

This single was the first release by Supercell which did not use the Vocaloid singing synthesizer Hatsune Miku as the vocalist, as they had done for their debut album Supercell (2009). Instead, Supercell employed the singer Nagi, a vocalist who had previously submitted cover versions of songs to the Nico Nico Douga video sharing website under the name Gazelle. The single peaked at No. 5 on Japan's weekly Oricon singles chart, and in February 2010 was awarded a Gold Disc by the Recording Industry Association of Japan for having exceeded 100,000 copies shipped in a single year.

The music video was shot in Chōshi, Chiba, Japan. Tokawa Station on the Chōshi Electric Railway Line and Inubōsaki lighthouse can be seen in the video. The video, directed by Hirohisa Sasaki, does not feature any members of Supercell nor the singer Nagi. Instead, the video prominently follows the actors Marika Fukunaga, Shuto Tanabe and Naho Kitade, who play members of a high school astronomy club with five others. Fukunaga, Tanabe and Kitade are in a love triangle where Fukunaga initially holds feelings for Tanabe, who pursues a relationship with Kitade. Time passes in the video, going through summer vacation and eventually graduation. As a parting gift, Tanabe gives Fukunaga his address, written on an ice cream stick, to where he is moving to in Tokyo, and he parts with Kitade at the train station, hinting that he broke off his relationship with Kitade to possibly start over with Fukunaga. More time passes, and Fukunaga is shown throwing the ice cream stick into the ocean after being reminded of the time she spent with Tanabe. The video ends with a flashback showing Fukunaga, Tanabe and Kitade happily gazing at the Summer Triangle at Inubōsaki lighthouse. The Summer Triangle is shown twice in the video as an allusion to the beginning of the second verse of the song which mentions it.