Cirno's Perfect Math Class

Cirno's Perfect Math Class

Part of a series on Touhou Project (東方Project). [View Related Entries]

Updated Jul 05, 2014 at 12:16AM EDT by VanManner.

Added Mar 30, 2011 at 05:21PM EDT by Hiroman.

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“Cirno’s Perfect Math Class” (Japanese: チルノのパーフェクトさんすう教室, Chiruno no Pāfekuto Sansū Kyōshitsu) is a musical arrangement created by the doujin group IOSYS that is based off the theme of Cirno, a popular boss character from the vertical shooter game Touhou Project. The song has since went on to become one of the most popular Touhou remixes upon it’s late 2008 release, with it and it’s music video inspiring many remix parodies and musical covers.


“Cirno’s Perfect Math Class” was written and arranged by members of IOSYS ARM, Yoshimi Tano, sung by miko, and was featured on the group’s album Touhou Anthology of Ice and Snow[1] (東方氷雪歌集, Tōhō Hyōsetsu Kashū), released at the Touhou convention Touhou Kouroumu 4 on November 2nd, 2008. In theme with the album, the song was an arrangement of Cirno’s boss theme “Beloved Tomboyish Girl” (おてんば恋娘, Otenba Koimusume), composed by Touhou creator ZUN for her appearance as the second boss in the Embodiment of Scarlet Devil.[2] To promote the album, the song was released online along with a flash-animated music video created by TETLA POT on the album’s now-defunct official site on October 25th, 2008.[3]

The flash-animation features many references within internet and pop culture in Japan, most notably includes the Colombia Pose and Kira Pose. The video also features many in-jokes known by fans of the Touhou series, which includes the nine-balls (⑨) during the chorus, which is in reference to Cirno’s label in the game’s layout screen in the Phantasmagoria of Flower View manual, where she is marked “9. Moron”. In turn, she is often portrayed by fans as being dim-witted and is associated with the nine-ball, or the number nine, and with the word “baka” (バカ), meaning idiot, moron, or fool in English.


Cirno’s portrayal of being “dim-witted” has been has a subject of fan-works and parody among Touhou fans after appearing in Phantasmagoria of Flower View in June 2005, often considered as one of the most widely known in-joke from the game. She has also been related to the subject of math teaching even prior to the song’s creation. For example, a flash game titled “Math Brain Training to become ⑨ Cirno”[4] (脳が⑨になるチルノの算数トレーニング) was created by flash game makers Chibitami on June 2008, where the objective is to answer a series of math questions incorrectly, all while choosing the number 9 as a sole answer.


Immediately after it’s online release, the music video for the song was then uploaded to the video-sharing site Nico Nico Douga on the same day.[5] The video became a massive hit among Touhou fans on the site, with it being viewed more than a million times in just two weeks. The full version of the song would later be leaked onto the site on October 31st, 2008[6], where it would receive more than 1.2 million views overall. With these of these uploads and with the ongoing popularity for IOSYS on Niconico, they would help inspire users on the site in creating a variety of MAD remixes of the song. One of the earliest of the mash-ups, featuring the Angry German Kid, was uploaded to Niconico on November 4th, while video that would become one of the top viewed remixes was uploaded the next day.

Featuring Shuzo Matsuoka, the video would receive more than 1.5 million views since its November 5th upload. As of July 2014, more than 3,600 video relating to the song has since been uploaded to Niconico[7], and with many have also been re-uploaded to YouTube.[8]

Dance Covers


In addition, the song has also been set to many collective dance performances. These performances were initially kick-started after a dance video performed by Niconico dancers Kyōfu. (恐怖。) and kuu. was uploaded to the site on November 9th, 2008. The video became one of the most popular within the “Odottemita” (踊ってみた, I tried dancing to) movement on Niconico, with over 1.4 million views. From this video, dance performances of the song began taking place within many prefectures in Japan and the number of participants expanding.

2010 Remake

A new version of the song titled “Cirno’s Perfect Health And Physical Education” (チルノのパーフェクトほけんたいいく, Chiruno no Paafekuto Hokentaiiku) was later created by IOSYS and featured on their album Touhou Love Strawberry Girl+[9] (東方恋苺娘+, Touhou Koi Ichigo Musume) at Comiket 78 on August 14th, 2010, where the subject has been changed to physical education.

Notable Examples

Musical Covers

Left: Piano Cover | Right: Violin Cover

Left: Metal Vocals Cover | Right: Dance Cover

MAD Parodies

Left: Yukkuri Parody | Right: Puyo Puyo!

Left: A Certain Magical Index | Right: Crazy Live Report

Search Interest

External References

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