The album includes Aragaki's previously digitally released "Walk" and "Chiisana Koi no Uta" (a Mongol800 cover) as well "Hanamizuki", a Yō Hitoto cover and theme song to Aragaki's film Hanamizuki.[2][3] It was released in three formats: CD-only standard edition, limited edition A, which has an illustration cover drawn by Aragaki and comes priced at 2,000 yen, and limited edition B, which comes with a bonus DVD that includes the music videos for "Chiisana Koi no Uta", "Walk" and "Hanamizuki".[2]
Niji debuted on the daily Oricon albums chart at #2 with 5,955 copies sold.[citation needed] It peaked at #4 on the weekly charts with 19,888 copies sold, making it Aragaki's third consecutive album to debut in the top 5.[citation needed]