Overview
もぺもぺ (Mopemope) is a BMS (Be-Music Source) track by composer LeaF with accompanying video by Optie, originally submitted to THE BMS OF FIGHTERS 2017 (BOFU2017) where it placed 3rd overall. The song is classified under the deliberately obscure genre label "イルーム音楽" (Iroom Music), a term that originated from a bug-play video and carries no formal definition, a fittingly cryptic banner for a piece defined by contrast and subversion. At a steady 100 BPM, the track begins as a gentle, pastoral melody before erupting into chaotic breakcore, mirrored by a music video that undergoes an equally jarring transformation from childlike innocence to grotesque horror imagery.
The video became the subject of significant notoriety both inside and outside the rhythm game community. YouTube's automated systems mistakenly classified it as child-friendly content (a phenomenon known as Elsagate), prompting Optie to file an appeal and add a prominent "This movie is NOT for children" disclaimer. When もぺもぺ was added to maimai DX Splash PLUS in March 2021, Sega implemented extensive censorship: the brief horror cuts in the first half are covered by mosaic blurring, and the extended horror sequence in the latter half is replaced entirely with stock footage of a ferry boat, a deliberate callback to the "Nice boat." meme from the School Days broadcast incident. The in-game title screen also displays "(※自主規制)" (self-censored) as a tongue-in-cheek acknowledgment.
Due to the video being an inseparable part of the work, Optie receives a joint artist credit alongside LeaF in the game, an unusual billing for maimai, where video creators are typically uncredited. The song has since appeared in numerous other music games including Taiko no Tatsujin, WACCA, PUMP IT UP, CHUNITHM SUN PLUS, Phigros, and Muse Dash, making it one of LeaF's most widely circulated compositions across the arcade and mobile rhythm game landscape.
Videos
Charts
DX
BASIC
3(3)
108 notesDesigner: -|Tap 82Hold 8Slide 3Touch 6Break 9
ADVANCED
8(8)
248 notesDesigner: -|Tap 159Hold 28Slide 11Touch 42Break 8
EXPERT
12+(12.8)
350 notesDesigner: シチミヘルツ|Tap 214Hold 34Slide 44Touch 24Break 34
MASTER
13+(13.9)
676 notesDesigner: さふぁた|Tap 305Hold 221Slide 40Touch 44Break 66
Trivia
- もぺもぺ was originally created for THE BMS OF FIGHTERS 2017 (BOFU2017), a long-running Be-Music Source tournament. It finished 3rd in the overall score ranking and 421st in the median score ranking.
- The genre label 'イルーム音楽' (Iroom Music) is not a formal music genre. It originated from a bug-play video and was adopted as a descriptive term for surreal, unsettling compositions.
- In the original BMS version, the final note triggers a sudden jump-scare: a realistic human hand bursts out from the center of the screen, an ending that was not carried into the arcade versions.
- WACCA's version of もぺもぺ was reportedly added without any modification to the video, though a pre-play warning informs players of the BGA content. PUMP IT UP applied scan-line blurring over the problematic sections.
- LeaF released an alternate version of もぺもぺ featuring only the peaceful first section, posted on Twitter during BOFU2017. A long version titled 'Mwfyuma Perustallora' appears on LeaF's album Doppelganger.
- The 'Nice boat.' replacement footage in maimai references a 2007 incident where the final episode of the anime School Days was replaced with scenic boat footage following a real-life murder that bore resemblance to the episode's plot. The phrase became an enduring internet meme.
- The companion title earned from playing もぺもぺ and True Love Song in the same credit is 'Nice boat.', a direct nod to the censorship meme.
- In the Chinese version of maimai (舞萌DX 2022), もぺもぺ was included from launch. It later appeared in the Chinese version of CHUNITHM (中二节奏 2025) as well.
- The Master chart (13+ / 13.9) was designed by さふぁた (Safata) and features an unusually high Hold note count of 221 out of 676 total notes, a distinctive structural choice that sets it apart from many other Master charts at this level.
- The Expert chart (12+ / 12.8) was designed by シチミヘルツ (Shichimi Hertz), with dense Touch note placements (42) relative to its level.
FAQ
- Who composed もぺもぺ?
- もぺもぺ was composed by LeaF, with the music video created by Optie. Both artists receive joint credit in maimai due to the video being an integral part of the work.
- What version of maimai added もぺもぺ?
- もぺもぺ was added to maimai DX Splash PLUS at launch on March 18, 2021, in both Japanese and Asian versions. It later appeared in the Chinese version of maimai DX 2022 and was ported to CHUNITHM SUN PLUS.
- Why is the もぺもぺ video censored in maimai?
- The original BGA by Optie includes graphic horror imagery that contrasts sharply with its childlike first half. In maimai, the horror cuts are blurred with mosaic patterns, and the long horror sequence is replaced with ferry boat footage, a reference to the 'Nice boat.' internet meme from the School Days anime incident.
- What difficulty levels do もぺもぺ have in maimai?
- もぺもぺ has four DX chart difficulties: Basic (level 3), Advanced (level 8), Expert (level 12+ / constant 12.8), and Master (level 13+ / constant 13.9). It does not have a Re:Master chart. The Expert chart was designed by シチミヘルツ and the Master by さふぁた.
- What does もぺもぺ mean or translate to?
- The title もぺもぺ (Mopemope) is a nonsense/onomatopoeic phrase without a fixed dictionary meaning. It is associated with the song's playful yet unsettling identity and is often romanized as 'Mopemope' or left in its original katakana form.
- What is イルーム音楽 (Iroom Music)?
- イルーム音楽 (Iroom Music) is the BMS genre label used for もぺもぺ in BOFU2017. The term originated from a bug-play video and is not a formal music genre; it is used informally to describe surreal, eerie, or unsettling compositions in the BMS community.
- What other rhythm games feature もぺもぺ?
- Beyond maimai, もぺもぺ appears in CHUNITHM SUN PLUS, Taiko no Tatsujin, WACCA, PUMP IT UP XX, Phigros, and Muse Dash.
