Based on Yūichirō Komikado's short story RGB, the song depicts relationships between childhood friends that are still connected even though they live in different places.

Ahamo, a mobile service by NTT Docomo, released and started broadcasting a new advertisement starring Nana Mori and Fūju Kamio on February 24, 2021.

[2][3] On June 14, cover artwork for "Sangenshoku" was revealed on the special website of the collaboration of Yoasobi and Uniqlo's T-shirt brand UT.

[5] Mikiki's Ryūtarō Amano has described "It is a great song that seems to be a condensed version of J-pop, Vocaloid culture, and J-rock, and the pop music of the era when hip-hop became the standard for the past 10 years".

[17] "Sangenshoku" debuted at number four on Billboard Japan Hot 100 for the chart issue date of July 7, 2021, behind BTS' "Butter", NEWS' "Burn", and Kenshi Yonezu's "Pale Blue".

[24][25] The short version of "Sangenshoku" music video, called Ahamo Special Movie, was uploaded on March 30, 2021, directed by Mado Matsumoto and illustrated by Jun Mutsuki.

[26] An official music video premiered on July 3 and was handled by animation studio CloverWorks, depicting the world view of the short story RGB.

Yoasobi performed "Sangenshoku" for the first time at the free online concert collaborated with Uniqlo's T-shirt brand UT, Sing Your World via the duo's official YouTube channel on July 4, 2021, where the song was the number one.