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BACK-ON × FLOW's ‘Kamen Rider’ Theme Song Out Now

BACK-ON × FLOW's joint ‘Kamen Rider Gotchard’ theme song ‘CHEMY×STORY’ gets full-length release!

The full-length single of BACK-ON and FLOW's special collaboration version of ‘CHEMY×STORY’ was released on February 7.

This new version became the theme song to TV series ‘Kamen Rider Gotchard’ in January,

replacing BACK-ON's original version of the same song which had soundtracked the show's opening since it began broadcasting in September 2023.

The new collaboration version with FLOW was announced at the end of the year, generating excitement from fans of ‘Kamen Rider’, BACK-ON, FLOW, and anime in general. Fans have enjoyed the “TV size” short version of BACK-ON × FLOW's ‘CHEMY×STORY’ since January while waiting patiently for the full-length version – and now it is available at last!

Don't miss this new version of ‘CHEMY×STORY’, arranged by FLOW, in all its glory.

Lyrics: Shōko Fujibayashi
Music: Hi-yunk (BACK-ON)
Arrangement: FLOW


▼ Comment from BACK-ON

“The story in ‘Gotchard’ is filled with twists and turns, and this seemed like the perfect timing to add a surprise twist to the opening theme song as well. We thought of this band as soon as this project first came along, and we wanted to go further than all the ‘Rider’ collaborations of the past, so we crashed through the boundaries to bring this track to life!

“I personally have admired FLOW since I was a teenager, and I had always wanted to have the opportunity to perform together with such a great band on a ‘Rider’ collaboration... Through this song, which has great chemistry with ‘Gotchard’, we want to convey each Sunday morning that dreams can come true if you keep pursuing them!

“We hope you enjoy the new ‘CHEMY×STORY’!”

▼ Comment from FLOW

“This collaboration was made possible when we were approached by the two members of BACK-ON. As fans since childhood, it was a pleasure to work on a song for our hero ‘Kamen Rider’. This is a song that could only have been made together with BACK-ON, so we hope you enjoy this unique chemical reaction, just like the fusion in ‘Kamen Rider Gotchard’.

“Let's all join together to enjoy ‘Kamen Rider Gotchard’.”



BACK-ON is a band consisting of MC TEEDA and vocalist/guitarist KENJI03, two childhood friends from Tokyo's Adachi Ward. They perform live not only in Japan but also in Asia, North America, Europe, South America and other parts of the world. They have received acclaim from listeners all around the world for their musicality and their live performances. In addition to writing their own material, they also write songs for many other artists.

Under the name Hi-yunk, KENJI03 previously composed the theme song ‘Trust · Last’ for ‘Kamen Rider Geats’, which was broadcast until August 2023, and the theme song ‘Change my future’ for ‘Kamen Rider Geats × Revice: Movie Battle Royale’. ‘CHEMY×STORY’ was his second theme song in a row for a new series of ‘Kamen Rider’. BACK-ON's song ‘Chair’ also featured in ‘Kamen Rider Geats’, marking the band's first contribution to the ‘Kamen Rider’ series as BACK-ON.


FLOW is a five-piece cross-genre rock band featuring KOHSHI (vocals), KEIGO (vocals), TAKE (guitar), GOT'S (bass) and IWASAKI (drums). Older brother KOHSHI and younger brother TAKE began their music career together in 1993, and formed FLOW in 1998. They were joined in 1999 by KEIGO and GOT'S, with IWASAKI rounding out the lineup in 2000.

Since making their major-label debut with the single ‘Blaster’ in 2003, FLOW have released hit after hit, boasting strong twin-vocal melodies and a wide musical palette. The band have released numerous anime theme songs, including the opening theme songs 'GO!!!' from ‘NARUTO’, ‘COLORS’ from ‘Code Geass: Lelouch of the Rebellion’, and ‘Kaze no Uta’ from ‘Tales of Zestiria the X’ – earning them a reputation as a band perfectly suited to anime.

FLOW celebrated their 20th anniversary on July 2, 2022; and on November 16 that year, they released the single ‘Daydream Believer’, a collaboration with ORANGE RANGE. In July 2023, they performed their largest ever headline concert, titled FLOW 20th ANNIVERSARY SPECIAL LIVE 2023 ~ANIMESHIBARI FESTIVAL~, which was held at Makuhari Messe International Exhibition Hall just outside of Tokyo.

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