Overview
カゲロウデイズ (Kagerou Days) is a landmark Vocaloid track by producer Jin (じん), featuring Hatsune Miku, that launched the sprawling Kagerou Project multimedia series. The song tells a tightly constructed narrative of a summer tragedy: a protagonist trapped in a time loop, repeatedly witnessing a fatal traffic accident on August 15th while the heat haze (陽炎 / kagerou) taunts her with the refrain "it's not a lie." Originally released on the 2011 compilation VOCAROCK collection 3 feat. 初音ミク, the track quickly became one of the defining Vocaloid songs of its era and the cornerstone of Jin's interconnected story universe spanning music, novels, manga, and anime. The music video, created by illustrator しづ (Shizu), established the distinctive character designs that would come to define the Kagerou Project's visual identity.
カゲロウデイズ joined maimai as a launch title in GreeN (July 2013) and has remained continuously available across all regions. Its relentless BPM of 200 and dense note patterns, particularly the Re:MASTER chart added in maimai MiLK (June 2018), demand sustained stamina from players. The chart has undergone numerous level revisions across every version from GreeN through BUDDiES, reflecting its ongoing relevance in the active song pool. The Expert and Re:MASTER charts were designed by はっぴー, while the MASTER chart was designed by ニャイン. The Re:MASTER in particular stands out for its extreme slide-note concentration (169 Slides against only 8 Holds), creating a breathless, forward-rushing pattern that mirrors the inescapable time loop at the heart of the song's story.
Videos
Charts
STD
BASIC
5(5)
147 notesDesigner: -|Tap 120Hold 12Slide 5Break 10
ADVANCED
7(7)
150 notesDesigner: -|Tap 96Hold 32Slide 18Break 4
EXPERT
11+(11.6)
405 notesDesigner: はっぴー|Tap 304Hold 78Slide 18Break 5
MASTER
13(13.2)
501 notesDesigner: ニャイン|Tap 380Hold 70Slide 30Break 21
Re:MASTER
14(14.1)
876 notesDesigner: はっぴー|Tap 688Hold 8Slide 169Break 11
Trivia
- カゲロウデイズ is the first song in Jin's Kagerou Project (カゲロウプロジェクト), a multimedia series that expanded into novels, manga, and the anime adaptation Mekaku City Actors.
- The title translates to "Heat Haze Days." The kagerō (陽炎), the shimmering heat haze seen on hot summer days, serves as a recurring visual and thematic motif throughout the entire Kagerou Project.
- The maimai version is a shortened edit of the full song, approximately 1:46 in length, compared to the 2:24 cut used in CHUNITHM.
- The music video was produced by illustrator しづ (Shizu), whose character designs define the visual identity of the Kagerou Project and its cast.
- In Asian English versions of maimai, the song is listed as "Kagerou Days" with the artist credited as "Jin."
- The Re:MASTER chart was added on June 5, 2018, as part of maimai MiLK, nearly five years after the song's original debut in GreeN.
- Playing カゲロウデイズ together with 夜咄ディセイブ and アウターサイエンス in a single session unlocks the title "それでは次の次の次で、また逢いましょう" ("Well then, see you in the next, next, next time"), a direct nod to the time-loop narrative.
- The song was featured in the 緑十段 (Green 10th Dan) 段位認定 course across multiple maimai versions, pairing it with other challenging tracks of its era.
- The MASTER chart by ニャイン sits at level 13 (constant 13.2), while the Re:MASTER by はっぴー pushes to level 14 (constant 14.1), distinguished by an unusually high Slide-to-Hold ratio, 169 Slides versus only 8 Holds.
- カゲロウデイズ also appears in SEGA's CHUNITHM series, added in CHUNITHM AMAZON PLUS (June 2019) and carried into CHUNITHM SUPER STAR at launch.
- The song was originally released on the compilation album VOCAROCK collection 3 feat. 初音ミク in 2011, before later being collected on Jin's own Kagerou Project albums.
- The lyrics establish the time-loop structure through specific date references: the accident occurs "around 12:30 PM on August 15th," and the protagonist wakes up "on the bed of August 14th," perpetually returning to the day before the tragedy.
FAQ
- Who composed Kagerou Days (カゲロウデイズ)?
- The song was composed, arranged, and written by Jin (じん), with vocals provided by Hatsune Miku. Jin is the creator of the broader Kagerou Project multimedia series.
- What is Kagerou Days about?
- The song tells a story of a summer tragedy involving a time loop. A girl witnesses a fatal traffic accident on August 15th and is caught reliving the events, taunted by a heat haze (kagerou) that insists the nightmare is real. The lyrics shift perspective each loop, gradually revealing the cycle.
- When was Kagerou Days added to maimai?
- It was added as a launch title for maimai GreeN on July 11, 2013, and has been continuously available across Japanese, International, USA, and Chinese regions since then.
- What difficulty is the Re:MASTER chart of Kagerou Days?
- The Re:MASTER chart is level 14 with a constant of 14.1, designed by はっぴー. It features 876 total notes, notably 169 Slide notes but only 8 Hold notes, creating a fast, slide-heavy pattern.
- Who designed the maimai charts for Kagerou Days?
- The Expert and Re:MASTER charts were designed by はっぴー, while the MASTER chart was designed by ニャイン. The Basic and Advanced charts have no credited designer.
- What is the Kagerou Project?
- The Kagerou Project (カゲロウプロジェクト) is a multimedia franchise created by Jin, centering on a group of characters with time-loop and eye-themed supernatural abilities. It began with Kagerou Days and expanded to include additional songs, novels, manga, and the anime adaptation Mekaku City Actors.
- What BPM is Kagerou Days?
- The song runs at 200 BPM, contributing to its intense, high-energy feel across all maimai chart difficulties.
- Does Kagerou Days appear in other rhythm games?
- Yes, it was also added to SEGA's CHUNITHM series, first in CHUNITHM AMAZON PLUS (June 2019) and later carried into CHUNITHM SUPER STAR. The CHUNITHM version uses a longer edit of the song (2:24).
