獅子志司 (Shishi Shishi) is a Vocaloid producer whose track 絶え間なく藍色 (Taemanaku Aiiro, "Ceaseless Indigo") features Hatsune Miku singing over a subdued, mid-tempo arrangement at 125 BPM. The title evokes an image of persistent, uninterrupted blue—a color often associated with melancholy or stillness in Japanese artistic contexts. The song joined maimai でらっくす Splash on October 1, 2020, as part of the niconico & Vocaloid genre lineup, and has remained a standard, always-available selection across all regions including Japan, international arcades, the United States, and China. In the maimai community, the track is best known for its Master chart (Lv13, difficulty constant 13.4) designed by Jack, whose pattern construction emphasizes Slide and Touch notes—109 and 35 respectively out of 646 total—giving the chart a distinctly different feel from speed-oriented Masters of the same level. The song's modest 125 BPM means the challenge comes from accurate execution across note-type transitions rather than raw hand speed. The Expert chart (Lv8) by はっぴー (Happy) offers a gentler introduction at 371 notes. A utage (宴/party) chart titled "藍" was later added under the designing alias 絶え間なく青色 ("Ceaseless Blue"), a color-based wordplay on the song's own title.