宙天 (Chuuten) is a collaborative original composition by two of rhythm gaming's most recognizable producers, t+pazolite and Kaneko Chiharu (かねこちはる), created for maimai DX PRiSM as part of the KALEIDXSCOPE -黒の扉- (Black Door) event series. The track is the pair's second joint work for the game, following 雨露霜雪 (Uro Sousetsu) from earlier in the same version. Where their first collab delivered sorrowful speedcore, 宙天 takes a markedly different direction: glitch hop anchored by a graceful piano motif, heavy hardcore kick patterns, and processed vocal samples that occasionally erupt into distorted screams. The song premiered publicly as the third track in the maimai DX division finals of KING of Performai The 6th. During that finals performance, a custom visual gimmick saw the artists' portraits swap between the two screens mid-song, the 1P side displayed Kaneko Chiharu then t+pazolite, while the 2P side showed t+pazolite then Kaneko Chiharu, creating a striking on-stage counterpart to the track's collaborative nature. The official video was produced by 川崎ヒロミツ (SIKAKU Inc.), with jacket and event illustrations credited to Metropolis Stories. The Master chart, co-designed by BELiZHEL and Safari, carries a level 14+ rating with a difficulty constant of 14.9 and ranks among the most note-dense songs in its tier at 1,058 total notes. Its defining structural quirk is a progressive BPM acceleration: starting at 125, the tempo rises by 5 BPM every measure through 130, 135, 140, 145, 150, 155, 160, 165, 170, 175, 180, 185, and finally 190, before abruptly halving to 95, a deceptive slowdown that has caught many players off guard. The Expert chart, designed by Jack, builds toward a Touch-note-heavy climax that players have compared to the notorious "umiyuri" (sea lily) patterns of Valsqotch, made especially tricky by the relatively slow tempo and added Tap notes on beats 2 through 4.