Renai Circulation

"Renai Circulation" (恋愛サーキュレーション) is a song from the 2009 Japanese anime television series Bakemonogatari (the animated adaptation of the first book from the Monogatari series by Nisio Isin) and performed by Kana Hanazawa as her character, Nadeko Sengoku. Composed by Satoru Kōsaki with lyrics written by Meg Rock, "Renai Circulation" serves as both Nadeko's character image song as well as the opening theme song in episode 10 of Bakemonogatari, which first premiered on September 11, 2009, to represent the "Nadeko Snake" story arc.

"Renai Circulation" was released on digital services and as a limited edition CD bonus with vol. 4 of the DVD and Blu-ray home releases of Bakemonogatari on January 27, 2010. It was later given a wider physical release and compiled on the series' soundtrack album, Bakemonogatari Ongaku Zenshū Songs &amp; Soundtracks on December 21, 2011.

"Renai Circulation" received praise for its "cute" melody as well as Hanazawa's vocals. After the initial release of "Renai Circulation", in 2010, the song inspired a trend of cover dances and mash-ups on Niconico. In the late 2010s, the popularity of the song resurfaced again, this time globally, through TikTok.

Background and release
"Renai Circulation" is a song from the 2009 anime series Bakemonogatari (the animated adaptation of the first book in the Monogatari series by Nisio Isin) and serves as the character image song for the character Nadeko Sengoku. It first appeared as the opening theme song of episode 10, "Nadeko Snake, Part 2", which was originally broadcast on September 11, 2009 on Tokyo MX, to coincide with "Nadeko Snake", a story arc featuring Nadeko as the main character. It is composed by Satoru Kōsaki with lyrics written by Meg Rock and vocals performed by Nadeko's voice actress, Kana Hanazawa. Kōsaki felt it would be interesting to feature Hanazawa rapping in a gentle manner, inspired by Shibuya-kei music and Japanese hip-hop artist Kaseki Cider.

Similar to Hanazawa's song "Melody", "Renai Circulation" is focused on a narrative with rap elements against a "funky tune." J-Cast described the song as a "light pop tune" that makes use of Hanazawa's vocals. Anime News Network described the song as a "starry-eyed love song" that reveals Nadeko's "conflict and character." The chorus opens with the Japanese onomatopoeia fuwa-fuwari (ふわふわり), which means "fluffy" and is used to describe "cute, upbeat, or insubstantial things." The song also contains a wordplay about Nadeko's name and yamato nadeshiko in the line "I will try without the 'shi' &mdash; I mean, I will try if it would cost my life!" (「し」抜きで いや 死ぬ気で！)

"Renai Circulation" was given a limited physical release as a CD bonus in vol. 4 of the DVD and Blu-ray limited edition home releases of Bakemonogatari. The home releases were originally scheduled to be on sale on December 29, 2009, but they were postponed until finally releasing on January 27, 2010. "Renai Circulation" was also released on digital services on the same day. On December 21, 2011, "Renai Circulation" saw a wider physical release on the soundtrack album Bakemonogatari Ongaku Zenshū Songs &amp; Soundtracks.

Reception
Famitsu stated that "Renai Cirulation" suited Nadeko's cute image "perfectly." They also describe Hanazawa to have an "airy" and "cute" singing voice that they found "charming." Anime News Network described the song as "cutesy as all get-out" and that it framed Nadeko as a "cute and dramatically vacuous", making her a cliché moe character. In 2019, "Renai Circulation" won the Character Song Award at the Heisei Anisong Grand Prix for the decade of 2000 to 2009.

Live performances
In 2015, Hanazawa performed "Renai Circulation" as an encore song for her "Live 2015 Blue Avenue" concert tour. After "Renai Circulation" went viral on TikTok in China, Hanazawa was invited to perform the song as a special guest at the 2019 BTV Universal New Year's Eve Snow and Ice Song Festival in Beijing, China. She later performed the song again in 2019 during a concert in Shanghai.

In 2022, Hanazawa performed "Renai Circulation" on her "Live 2022 Blossom" concert tour. She also performed it at Animelo Summer Live 2022. In 2023, she performed the song at the Tencent Music Entertainment Awards as part of a medley of her other anime songs.

Cultural impact
After the song's initial release, in 2010, "Renai Circulation" became a hit among anime fans, inspiring cover dances with original choreography and song mash-ups on Niconico. Nadeko won first place in a Bakemonogatari character poll held by anime merchandise retailer Toranoana, with some voters citing "Renai Circulation" as the reason. In 2022, Hanazawa stated that the success of "Renai Circulation" led her to receiving more offers to perform character songs as well as a singing career. She also stated that the song has helped her "get to know [her] voice."

In 2018, "Renai Circulation" went viral on TikTok in China. On December 18, 2019, Chinese electronics company Xiaomi posted a parody version of the song video on Bilibili about their Q3 financial report using processed voice clips from their CEO, Lei Jun. In 2021, "Renai Circulation" spread outside of Asia on TikTok as well through a 2012 English-language cover version by American singer Lizz Robinett. Robinett's version inspired cover dances on the app and became an Internet meme. Her version of the song also saw popularity with Japanese users who were unfamiliar with the song. "Renai Circulation" was described by Natalie as an example of a J-pop song finding a global audience.

The song "Tokyo Mauve" by Polkadot Stingray was inspired by Hanazawa, with the composition resembling "Renai Circulation." In 2022, "Renai Circulation" was used as an ending theme song to the child-rearing program Sukusuku Ko Sodate on NHK Educational TV.

Cover versions
In 2010, Japanese singer Mai Kotone recorded a cover version for Anime Dance Best Gig, a compilation album featuring covers of popular anime songs. Kotone also performed the song during a concert celebrating her 24th birthday in 2014. In 2012, American singer Lizz Robinett recorded an English-language cover, which later spread outside of Asia on TikTok. Robinett's version ranked no. 1 in the Billboard Japan TikTok Weekly Top 20 in the week of March 22, 2021. In 2013, Japanese singer Nagi Yanagi recorded a cover version as a first press bonus for her album Euaru. In 2020, a Chinese-language cover version was recorded and performed on the reality competition program Youth With You. In 2022, a cover version performed by Hotaru Shiragiku (voiced by Satomi Amano) became available as a playable song in the mobile game The Idolmaster Cinderella Girls: Starlight Stage. The Resonanz Children's Choir performed the song live with the Jakarta Concert Orchestra, during an Anime Symphony concert.