Monochrome Rainbow is a maimai original song created by Sta (Yasutaka Senoo), a multi-talented artist active in both music production and video art. Added during the GreeN PLUS era in February 2014, it was one of the earliest original compositions commissioned for the series and remains a distinctive entry in the maimai catalog. The track is a piece of progressive techno music characterized by intelligent synthesizer work intertwined with lo-fi drum patterns and bass. A whisper-style vocal, performed by Sta alongside lyricist Call, drifts through the arrangement, creating an atmospheric, floating quality that rewards headphone listening with its spatial stereo imaging. The soundtrack booklet describes the opening section's immersive soundscape, where lo-fi drums weave around polished synth pads in a way that feels both grounded and ethereal. The title plays on conceptual contradiction: a rainbow defined by the absence of color. Sta's accompanying animated music video, which he created himself, reinforces this theme with monochrome character art and minimalist monochromatic graphics. In his artist comment, Sta reflected on his own childhood playing arcade rhythm games, recalling how staff would bring him a step stool because he was too short to reach the cabinet, and expressed hope that young players today might someday channel that inspiration into their own creative work. This sentiment gives the "monochrome rainbow" its emotional core: a blank canvas waiting for color. Nearly a decade after its debut, Monochrome Rainbow received DX charts in June 2023 as a Friend Matching Season 11 reward, extending the song into the Touch-note era with redesigned Expert and Master charts by サファ太 and Jack respectively. The Standard Master chart, originally rated level 11 at launch, has been re-leveled multiple times across version updates to its current 13.0 rating, a trajectory that mirrors the series' evolving difficulty calibration over the years.