真空都市 (Shinkuu Toshi, "Vacuum City") is a maimai original song introduced in maimai でらっくす CiRCLE, performed by the unit ナナツカゼ (Nanatsukaze). The track was composed and arranged by PIKASONIC, with lyrics and vocals by nakotanmaru, and accompanied by a music video created by ﾅﾑﾙ and gaogao. At 185 BPM with a length of 2:33, the song sits in the energetic upper range of rhythm-game originals while carrying a surprisingly introspective lyrical and narrative weight. The song is paired with a flavor text story about a striped sparrow who, after wandering into the sunken ruins of a lost civilization, becomes captivated by the ancient concept of "fashion" (おしゃれ). Rejecting her mother's explanation that beautiful colors are merely a survival strategy, the sparrow decides to spread the forgotten ideal of self-expression to everyone. This whimsical yet earnest narrative mirrors the lyrics, which question whether visible reality is all that exists and explore themes of creation, destruction, and the search for meaning in a desolate "vacuum city." Unlocked in the kawaii Area 2 (kawaiiちほー2) by accumulating 75 km of travel distance, 真空都市 blends the area's cute aesthetic with a darker thematic undercurrent. Its DX charts are crafted by two notable designers: Luxizhel handled the Expert (level 10+) chart, while サファ太 (Safata) designed the Master (level 13) chart, the latter carrying 752 total notes and a difficulty constant of 13.4. In the Asian version of the game, the song became available on March 19, 2026.