Calamity Fortune is a high-energy Touhou Project arrangement by the prolific BMS and rhythm-game composer LeaF, based on ZUN's "少女が見た日本の原風景" (The Japanese Landscape the Girl Saw), the Stage 1 theme from Touhou Fuujinroku ~ Mountain of Faith. The track originated from the BMS (Be-Music Source) event 東方音弾遊戯5 (Touhou Ondan Yuugi 5), a community competition that produced many Touhou arrangements later adopted by commercial arcade rhythm games. It made its rhythm-game debut in Sega's CHUNITHM STAR before arriving in maimai MURASAKi PLUS on December 5, 2017. At a relentless 200 BPM with a pounding electronic arrangement built on LeaF's signature dense melodic writing, Calamity Fortune quickly established itself as a boss-class track in both maimai Standard and DX chart pools. The Standard MASTER chart, designed by 小鳥遊さん, stands at Level 14 (constant 14.2) with 1,142 notes, one of the most demanding Standard charts from the MURASAKi PLUS era. The DX MASTER chart, designed by シチミヘルツ, is rated Level 13+ (constant 13.6) and integrates Touch notes extensively into its 935-note layout. Both EXPERT charts, by 玉子豆腐 (Standard, Level 12+) and 某S氏 (DX, Level 11), are likewise formidable. A long version of Calamity Fortune appears on LeaF's debut solo album Doppelganger, and the song has since been featured in オンゲキ PLUS (with a LUNATIC chart), 太鼓の達人 (Taiko no Tatsujin), and Muse Dash.