Overview
"チルノのパーフェクトさんすう教室 ⑨周年バージョン" (Chiruno no Perfect San'suu Kyoukai ⑨ Shuunen Version, or Cirno's Perfect Math Class ⑨th Anniversary Version) is a celebratory Touhou doujin arrangement marking nine years since the original 2008 song "Chiruno no Perfect San'suu Kyoukai" first appeared on the IOSYS-produced album "Touhou Hyousetsu Kashuu." The original quickly became one of the most recognizable Touhou fan songs, and this anniversary edition was re-recorded with an expanded collaborative lineup: IOSYS joined forces with six major doujin circles, Yuuryoku Satellite, A-One, Butaotome, COOL&CREATE, TaNaBaTa, and Alternative ending, collectively credited as "IOSYSと愉快な⑨周年フレンズ" (IOSYS and Happy ⑨th Anniversary Friends). True to Cirno's iconic association with the number 9, the song's release was timed with meticulous ⑨-themed precision: the YouTube premiere was set for 2017/9/9 at 09:09 JST. The number 9 (⑨) also permeates the in-game chart design, most notably in the Standard charts where every difficulty features Break note counts of exactly 9 or 99.
Videos
Charts
DX
BASIC
3(3)
146 notesDesigner: -|Tap 90Hold 39Slide 4Touch 6Break 7
ADVANCED
7(7)
289 notesDesigner: -|Tap 220Hold 26Slide 6Touch 11Break 26
EXPERT
9(9)
479 notesDesigner: サファ太|Tap 341Hold 63Slide 27Touch 38Break 10
MASTER
12+(12.8)
740 notesDesigner: 華火職人|Tap 483Hold 53Slide 60Touch 102Break 42
Trivia
- The song is based on Cirno's theme 'Otenba Koimusume' (おてんば恋娘, 'The Tomboyish Girl') from Touhou Koumakyou ~ the Embodiment of Scarlet Devil.
- The original 2008 'Chiruno no Perfect San'suu Kyoukai' was released on IOSYS's doujin album 'Touhou Hyousetsu Kashuu' (東方氷雪歌集).
- The YouTube upload of this anniversary version was deliberately scheduled for 2017/9/9 at 09:09 JST, every digit a 9, though YouTube's Pacific Time (PDT-7) clock displayed it as September 8th.
- Six guest circles collaborated on this track alongside IOSYS: Yuuryoku Satellite, A-One, Butaotome, COOL&CREATE, TaNaBaTa, and Alternative ending.
- All Standard-format charts for this song feature Break note counts of exactly 9 or 99, a deliberate nod to Cirno's ⑨ meme.
- The Standard EASY chart (no longer listed in current version data) had only 99 total notes, with Tap, Hold, and Slide each counting 9.
- This song appears as the second track in the maimai 'Hakukudan' (White 9-dan) rank certification course, alongside Magical Flavor, Nansense Bungaku, and Moushin Soloist Life!.
- The Standard Master chart, designed by 小鳥遊さん (Takanashi-san), is rated level 13 with 771 total notes, including 99 Break notes.
- The DX Master chart, designed by 華火職人 (Hanabi Shokunin), carries a difficulty constant of 12.8 and features 102 Touch notes alongside 42 Break notes.
- Level constants for this song have shifted across maimai versions: Standard Expert rose from 9 to 10+ over the game's lifespan, and Standard Master increased from 12 to 13.
FAQ
- Who produced Chiruno no Perfect San'suu Kyoukai ⑨ Shuunen Version?
- The song was produced by the doujin circle IOSYS in collaboration with six guest circles, Yuuryoku Satellite, A-One, Butaotome, COOL&CREATE, TaNaBaTa, and Alternative ending, collectively credited as 'IOSYSと愉快な⑨周年フレンズ' (IOSYS and Happy ⑨th Anniversary Friends).
- What does the ⑨ in the title refer to?
- The ⑨ (nine) is a longstanding meme in the Touhou fandom associated with the character Cirno, who is often called 'baka (idiot) ⑨.' The number appears throughout the song's release timing (2017/9/9 at 09:09) and chart design (Break notes are always 9 or 99) as a running thematic joke.
- Which maimai version added this song?
- The Standard-format charts debuted in maimai MURASAKi PLUS on October 17, 2017. DX-format charts were added later on July 11, 2019, alongside the maimai DX (でらっくす) update.
- Who designed the Expert and Master charts?
- The Standard Expert chart was designed by はっぴー (Happii) and the Standard Master by 小鳥遊さん (Takanashi-san). The DX Expert was designed by サファ太 (Safata) and the DX Master by 華火職人 (Hanabi Shokunin).
- Why do the Standard charts have so many 9s in their note counts?
- Every Standard chart for this song has Break note counts of exactly 9 or 99, a deliberate design choice that references Cirno's ⑨ meme. Additionally, the old Standard EASY chart had 99 total notes with Tap, Hold, and Slide each at exactly 9.
- Is this song based on an original Touhou track?
- Yes, it is an arrangement of Cirno's theme 'Otenba Koimusume' (おてんば恋娘, 'The Tomboyish Girl') from Touhou Koumakyou ~ the Embodiment of Scarlet Devil, the sixth game in the Touhou Project series.
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