Yoasobi (stylized in all caps) is a Japanese music duo composed of vocaloid music producer Ayase and vocalist Ikura. The group has released four music videos, all of which are based on short stories posted on Monogatary, a website operated by Sony Music Japan. Both members of Yoasobi had active music careers prior to forming the group. Ayase gained a following on the video hosting site Niconico since his first upload on 24 December 2018, a song titled Sentensei Assault Girl (先天性アサルトガール). On 23 November 2019, he released an EP, Yūrei Tōkyō (幽霊東京), which reached third on iTunes' album chart. Ikuta, performing under the name Rira Ikuta (幾田りら), had already released two EPs: Rerise in 2017 and Jukebox in 2019. The first song released by the duo was "Yoru ni Kakeru", based on Mayo Hoshino's short story "Thanatos no Yūwaku" hosted on Monogatary. The music video was released first on 16 November 2019, where it broke 10 million views in five months on YouTube as well as being popular on TikTok. It was subsequently released as a single on 15 December 2019, where it topped the popularity charts on both Spotify and Line Music.[5] More than five months after its release, the single would top the Billboard Japan Hot 100 on 1 June 2020.[6] Following the success of their first release, on 18 January 2020, Yoasobi released their second single, "Ano Yume o Nazotte", this time based on Sōta Ishiki's "Yume no Shizuku to Hoshi no Hana". On 20 April 2020, Yoasobi released a teaser for their third single, "Halzion", which is based on Shunki Hashizume's "Soredemo, Happy End". "Halzion" marked the first time that Yoasobi collaborated with a professional novelist, whereas the first two were amateur writers. The single was released as a promotional project by Suntory to advertise their new energy drink named Zone. The single was official released on 11 May 2020. Official website: https://www.yoasobi-music.jp/ Twitter: https://twitter.com/yoasobi_staff YouTube: https://www.youtube.com/channel/UCvpredjG93ifbCP1Y77JyFA