IOSYS

IOSYS is a Japanese musical ensemble and dōjin circle based in Sapporo. The group is best known for producing unofficial arrangements of music from the Touhou Project series of shoot-'em-up games, while also working with material associated with other games and Japanese pop-culture properties. Rather than operating as a conventional recording artist signed to a major label, IOSYS has historically used Japan's dōjin distribution ecosystem, releasing independently produced albums through events such as Comiket and through its own website. The circle's public identity combines music, parody, illustration, animation, and internet-native promotion. Its arrangements often transform source melodies into comic songs, character parodies, novelty dance tracks, or aggressively stylized electronic productions. This approach helped IOSYS stand out within the Touhou arrangement scene, where multiple independent circles commonly reinterpret the same original compositions. The group has also written and performed music connected with anime and other game-related projects, extending its activity beyond Touhou fan works. IOSYS's breakthrough period came in the mid-2000s. In April 2006, it released a Flash music video for the original song "Farewell 2005," created by the dōjin animation producer Kagi, also known as locker room production. After being impressed by Kagi's earlier animation "NANAME City," IOSYS invited the animator to make visual works for the circle. In May 2006, IOSYS issued its first Touhou arrangement album, "Tōhō Kazakuraen." A second album, "Tōhō Otomebayashi," followed in August, and its song "Marisa Stole the Precious Thing" received an animated promotional video in November. That work became one of the circle's defining pieces and helped establish IOSYS's distinctive blend of parody, fan culture, and short-form animation. Further releases and collaborations reinforced that reputation. The circle created or contributed to animated works associated with songs such as "Stops at the Affected Area and Immediately Dissolves ~ Lunatic Udongein," commonly referred to in English-speaking fan communities as "Overdrive," and "Cirno's Perfect Math Class." These videos circulated widely through Japanese internet forums and video platforms including Nico Nico Douga and YouTube. Their unauthorized reposting also illustrated the tension between dōjin creators' independently controlled works and the rapid, largely informal distribution practices of online fan communities. IOSYS has also contributed music to commercial and broadcast-oriented projects. It produced the second ending theme for "Penguin Musume Heart" and supplied opening and ending music for "Yumekui Merry." In the 2020s, the circle collaborated with virtual YouTuber Shigure Ui on the track "Shukusei! Loli Kami Requiem," which gained substantial attention in Japan through TikTok and YouTube. On August 21, 2024, McDonald's Japan worked with IOSYS and Team Shanghai Alice on a parody advertisement based on "Marisa Stole the Precious Thing," featuring new vocals by miko and new visuals by Kagi. This collaboration brought a work rooted in dōjin and internet culture into a mainstream national advertising campaign. IOSYS therefore occupies an unusual position: it is simultaneously a fan-music circle, an independent publishing identity, an animation-associated creative brand, and a contributor to commercial media projects. Its importance rests less on conventional chart activity or corporate scale than on its influence within Touhou fandom, Japanese internet culture, and the broader dōjin music economy.

IOSYS emerged as a Sapporo-based Japanese dōjin music circle and ensemble operating outside the conventional major-label system. Its activities developed within the independent creator culture surrounding Comiket, fan-made music, game-music arrangements, and online video. The circle's core format combined original and rearranged songs with visual parody, often using animated or Flash-based music videos to give the music a strong internet identity. The first Flash music video associated with IOSYS was made for "Farewell 2005" and published in April 2006. The animation was created by Kagi, also known as locker room production. IOSYS had become interested in Kagi after seeing the earlier animation "NANAME City" and subsequently invited the animator to produce visual material for the group. This relationship became important to the circle's recognizable audiovisual style. In May 2006, IOSYS released "Tōhō Kazakuraen," its first album of Touhou Project arrangements. The group followed it with "Tōhō Otomebayashi" in August. In November of that year, IOSYS published a promotional video for the album's second track, "Marisa Stole the Precious Thing." The song and video became a signature work, receiving strong attention among visitors to Japanese internet forums and fan communities. The circle continued developing the same formula through later Touhou arrangement albums and videos. "Stops at the Affected Area and Immediately Dissolves ~ Lunatic Udongein," made in collaboration with COOL&CREATE and commonly called "Overdrive" by some English-speaking fans, and "Cirno's Perfect Math Class" became prominent examples of IOSYS's comic, highly stylized approach. Their Flash movies and fan-made reposts spread through Nico Nico Douga, YouTube, 2channel-related communities, and other otaku internet networks. The scale of this circulation helped IOSYS become one of the more visible names in the Touhou arrangement scene, although the unauthorized uploading of its videos also meant that circulation frequently occurred without the creators' permission. IOSYS later expanded beyond fan arrangements. It produced the second ending credits music for "Penguin Musume Heart" and composed opening and ending credits music for "Yumekui Merry." These projects demonstrated that the circle's creators could move between dōjin releases and commissioned or associated anime work without abandoning their independent identity. Its later activity included collaborations with online creators and virtual performers. A special track made with Shigure Ui, "Shukusei! Loli Kami Requiem," attracted attention through TikTok and YouTube, reflecting the continued relevance of IOSYS's hook-oriented, meme-compatible production style in newer social-media environments. On August 21, 2024, McDonald's Japan collaborated with IOSYS and Team Shanghai Alice on a parody commercial based on "Marisa Stole the Precious Thing." The campaign used new vocals by miko and new visuals by Kagi, linking a work from the mid-2000s dōjin internet scene to a mainstream advertising platform. IOSYS's historical significance comes from this sustained movement across cultural boundaries. It has maintained a dōjin-circle mode of production while achieving recognition through fan conventions, video platforms, anime-related work, virtual-creator collaboration, and national advertising. The circle is best understood as a creative collective and media identity rather than as a conventional record-company brand.

• 2024

  McDonald's Japan parody campaign

  [1]IOSYSen.wikipedia.org

  McDonald's Japan collaborated with IOSYS and Team Shanghai Alice on a new parody advertisement using the circle's signature Touhou-related song.

• 2016

  Maron joins IOSYS

  [1]IOSYSen.wikipedia.org

  Composer, lyricist and DJ Maron joined the circle.

• 2010

  uno joins IOSYS

  [1]IOSYSen.wikipedia.org

  Composer and DJ uno, also known as RoughSketch, joined in July.

• 2007

  Yuya Kobayashi joins IOSYS

  [1]IOSYSen.wikipedia.org

  Composer and arranger Yuya Kobayashi, also known as void, joined the circle.

• 2006

  First IOSYS Flash music video

  [1]IOSYSen.wikipedia.org

  A Flash music video for "Farewell 2005" was published, beginning the prominent relationship between IOSYS's music and Kagi's animation work.

• 2006

  First Touhou arrangement album

  [1]IOSYSen.wikipedia.org

  IOSYS released "Tōhō Kazakuraen," its first Touhou Project arrangement CD.

• 2006

  Release of Tōhō Otomebayashi

  [1]IOSYSen.wikipedia.org

  The second Touhou arrangement album was released in August.

• 2006

  Marisa Stole the Precious Thing video

  [1]IOSYSen.wikipedia.org

  IOSYS published an animated promotional video for "Marisa Stole the Precious Thing," which became one of its best-known works.

An independent Japanese dōjin music and multimedia circle focused on humorous, character-driven arrangements, electronic production, parody, and animation-led internet distribution.

• Touhou arrangement album · 2006

  Tōhō Kazakuraen

  Released in May 2006, this was IOSYS's first Touhou Project arrangement CD. It established the circle's participation in the independent fan-music scene and its practice of reworking music from the Touhou game series.

• Touhou arrangement album · 2006

  Tōhō Otomebayashi

  The second Touhou arrangement album, released in August 2006. Its track "Marisa Stole the Precious Thing" later became the basis for one of IOSYS's most recognizable animated music videos.

• Arrangement song and animated music video · 2006

  Marisa Stole the Precious Thing

  This humorous Touhou arrangement became a signature IOSYS work after the group released an animated promotional video in November 2006. Its visual and musical style helped define the circle's early internet-era reputation and later supported a mainstream McDonald's Japan parody campaign.

• Touhou arrangement song and Flash video

  Stops at the Affected Area and Immediately Dissolves ~ Lunatic Udongein

  A prominent IOSYS arrangement from the album "Rabbi-Tewi," made in collaboration with COOL&CREATE. It is also known in some English-speaking fan circles as "Overdrive" and was accompanied by a widely circulated animated work.

• Touhou arrangement song and animated music video

  Cirno's Perfect Math Class

  A comic, character-focused Touhou arrangement associated with IOSYS's Flash-video period. Like the circle's other viral works, it spread through Japanese internet communities and video-sharing platforms.

• Collaborative digital song

  Shukusei! Loli Kami Requiem

  A collaboration between IOSYS and virtual YouTuber Shigure Ui. The track gained significant attention in Japan through TikTok and YouTube, showing the circle's continued connection to meme-driven online music culture.

• 2024McDonald's Japan Touhou parody advertisement

  Japan

  McDonald's Japan collaborated with IOSYS and Team Shanghai Alice on a parody advertisement based on "Marisa Stole the Precious Thing." The campaign used new vocals by miko and new visuals by Kagi.

  Outcome. The campaign connected a well-known dōjin and internet-culture work with a major national consumer brand.

  Source

• Independent dōjin distribution instead of conventional label signingStrategy

  Background

  IOSYS developed within Japan's dōjin music ecosystem, where creators distribute works through events such as Comiket and through their own channels.

  Action taken

  The circle retained an independent release model rather than signing with a conventional record label.

  Aftermath

  This model supported direct access to fan communities and allowed IOSYS to combine music, parody, animation, and online promotion.

  Source

1. 1IOSYSen.wikipedia.org
2. 2IOSYS official websiteiosysos.com