Besides "Yoru ni Kakeru", three other songs were also certified diamonds: Blue Period-inspired "Gunjō" and opening themes for anime Beastars "Kaibutsu" and Oshi no Ko "Idol"; the latter set the record for the longest-running number one on the Japan Hot 100 history with 22 non-consecutive weeks, and the first Japanese act to top the Billboard Global Excl.

[1] To represent themselves, Yoasobi uses the slogan "novel into music" (Japanese: 小説を音楽にするユニット, Hepburn: shōsetsu o ongaku ni suru yunitto, lit.

[6] In 2016, she participated in a new artist training course, called the Lesson, sponsored by Sony Music Entertainment Japan, and released her demo CD 15 no Omoi.

[8][9] In 2019, Yohei Yashiro, a founder of Monogatary.com, a social media for creative writing owned by SMEJ, presented the idea of project to produce songs inspired by selected story submissions published on the website as a prize to authors instead of book or anime adaptation, which not all were successful.

[15] The first song released by Yoasobi, "Yoru ni Kakeru", was based on the short story Thanatos no Yūwaku written by Mayo Hoshino, which won the novel contest Monocon 2019.

Like "Yoru ni Kakeru", the song is based on another Monocon 2019-winning short story by Sōta Ishiki, Yume no Shizuku to Hoshi no Hana.

[33] The next single, "Halzion", sourced from Shunki Hashizume's Soredemo, Happy End, was released on May 11 as part of Suntory's "Immersive Song Project" to advertise energy drink Zone.

[36] Inspired by the manga series Blue Period and sourced from the short story written by the brand's creative team Ao o Mikata ni, "Gunjō", featuring uncredited chorus of Plusonica, was released on September 1.

[38] On December 31, Yoasobi concluded 2020 at the year-end television special 71st NHK Kōhaku Uta Gassen with the debut live performance of "Yoru ni Kakeru" as a duo, along with band members, filmed at Bookshelf Theater, Kadokawa Culture Museum in Tokorozawa.

[60] In support of The Book, the duo held their first livestream concert, Keep Out Theater, on February 14 at the construction site of former Shinjuku Milano-za (today Tokyu Kabukicho Tower) for 40,000 online audiences.

[64] A song for NTT Docomo's mobile network operator Ahamo commercial, "Sangenshoku", based on scriptwriter Yūichirō Komikado's RGB,[65] was released on July 2.

The EP features the duo's all singles released in that year, including "Moshi mo Inochi ga Egaketara",[75] a theme for and based on the 2021 play of the same name written and directed by Osamu Suzuki, performed in August and September 2021.

[80] The duo participated in the 72nd NHK Kōhaku Uta Gassen on December 31,[81] to perform "Gunjō" for the main show featuring a symphony orchestra,[82] and "Tsubame" as part of "Colorful Special Segment" with Midories and mascots from Hirogare!

It contains Rio Shimamoto's Watashi Dake no Shoyūsha, Mizuki Tsujimura's Yūrei, Miyuki Miyabe's Iro Chigai no Trump, and Eto Mori's Hikari no Tane.

[112][113] In 2023, Yoasobi was in charge of the opening theme of the anime series Oshi no Ko, titled "Idol",[114] based on manga artist Aka Akasaka's short story 45510, released on April 12.

!, for the remake of "Chūō Freeway", originally from 14 Banme no Tsuki (1976),[142] adding new materials sourced from Matsutoya's biographical novel Subete no Koto wa Message Shōsetsu Yuming (2022) by Mariko Yamauchi.

[143] They also participated in the seventh iteration of television special 18Fes,[144] singing one-time-only "Heart Beat" with 1,000 teenagers between 17 and 20 years old,[145] broadcast on December 25 and the song was released the next day.

[155] In the same month, they were invited for the US President Joe Biden-hosted state dinner for Japanese Prime Minister Fumio Kishida at the White House,[156] and signed an agent contract with American Creative Artists Agency.

[163] In the same month, on July 25, the duo released "Butai ni Tatte", a theme for NHK's 2024 coverage of sports events, including the Summer Olympics and Paralympics, based on Jun Esaka's short story version of three one-shot manga: Taizan 5's Hanareta Futari, Yūki Kirishima's Parallel Lane, and Hirusagari Haruno's Owaranai Deuce.

[172] The song was sourced from Mado Arite's short story Hakusan-dōri Enjō no Ken, winning Bungei × Monogatary.com Collaboration Award at the Monocon 2023,[173] and used as a jingle for Recruit's second part of Mada, Koko ni Nai, Deai, Koko ni Nai, Ongaku project commercial, "Wakaranai mama, Sore de mo".

[177] They scheduled to participate at Primavera Sound in Barcelona, Spain, hold a one-off concert in London, England in June,[178][179] and embark on their Japan Hall Tour from July to November.

[181] The Asahi Shimbun described their songs contain "complex structures with shifting rhythms and key changes", and "catchy melodies and memorable hooks", and Ikura's vocals "effortlessly clear[ing] high notes and sails through rapid-fire lyrics in time with their tempos, even showing off some playful rap [...].

[13] Ayase named Aiko, Exile,[13] Post Malone,[183] and rock bands: Sukima Switch, Kobukuro,[184] Radwimps,[14] Maximum the Hormone, Coldrain, Crossfaith, SiM, Slipknot, and Bring Me the Horizon;[185] and Ikura cites Taylor Swift as each major music influence.

[190] Music director and record producer Konnie Aoki is usually in charge of translating Yoasobi's songs into English, which he uses word choices that maintained the rhythm of the original Japanese lyrics.

Described by themselves as having "DIY", "hands-on", and "handmade" styles, when writing music for the duo, Ayase first creates a demo by using digital audio workstation Logic Pro on his laptop with Vocaloid software, mostly Hatsune Miku, allowing him to avoid any distortion based on a human vocalist's interpretation, then records Ikura's vocals afterwards.

[194][195] Writing for Real Sound, Natsume Sogami described Yoasobi's music as "derivative work", which creates style contrasting to other musicians and songwriters.

[189] Pen's Hiroaki Nagahata wrote that the duo's songs "reflect modern motifs, including negative things that no one would dare say in public.

[197][198] To promote the collaboration, they held the free livestream concert Sing Your World at Uniqlo City Tokyo and broadcast via the duo's official YouTube channel on July 4, which received 280,000 online viewers globally.

[201] In June 2023, Super Cup 1.5x partnered with the duo to produce two special flavors for instant noodles: Ikura's salted tonkotsu and Ayase's spicy soy sauce.

[206] Sportswear brand Asics partnered with Yoasobi for pop-up gallery Just a Little Step at Rayard Miyashita Park between November 1 and 10, and scheduled to launch collaborative products in 2025.