疾走あんさんぶる (Shissou Ensemble) is a high-speed Touhou Project arrange by ビートまりお (beatMARIO), the prolific vocalist and composer from the doujin circle COOL&CREATE. The track reimagines 幽霊楽団 ～ Phantom Ensemble, the stage 4 boss theme from 東方妖々夢 ～ Perfect Cherry Blossom (2003), the eighth mainline Touhou game by ZUN (Team Shanghai Alice). Originally released on COOL&CREATE's 2004 album 東方ストライク, the song lives up to its name, "Sprinting Ensemble", with a breakneck BPM of 195 and beatMARIO's signature high-energy vocal delivery that turns the original waltz-like melody into a frantic dash. In the maimai series, 疾走あんさんぶる joined maimai MiLK on May 8, 2018, but not before making a cheeky debut as an April Fools' UTAGE (banquet) chart available for just one week (April 1–8, 2018). That UTAGE chart, designed for three players simultaneously, carries 1,365 notes, the second-highest note count of any maimai chart to date, behind only FREEDOM DiVE (tpz Overcute Remix). Originally labeled "3人用！？（上・左下・右下）" ("For 3 people!? (Top, bottom-left, bottom-right)"), the chart was later renamed "なりきれ！プリズムリバー三姉妹" ("Become the Prismriver Trio Sisters!") when it was revived in maimai DX BUDDiES. The jacket art and music video were produced by ツナマヨ, with the video reportedly drawing inspiration from a NicoNicoDouga fan animation first published in 2009. The standard chart set features an Expert chart (level 11+, constant 11.6) designed by はっぴー and a Master chart (level 13+, constant 13.7) designed by 某S氏. The Master chart is a high-speed endurance test: 890 notes packed into 2 minutes and 9 seconds, with dense Tap clusters punctuated by 104 Slide notes that demand precise spatial awareness. Beyond maimai, the song has crossed over into sibling SEGA rhythm titles オンゲキ and CHUNITHM, making it one of the more widely circulated Touhou arranges in the SEGA arcade ecosystem.