Satoru Kōsaki (神前 暁, Kōsaki Satoru, born September 16, 1974) is a Japanese music composer and arranger. He is best known for his work on anime, including Lucky Star, The Melancholy of Haruhi Suzumiya, Monogatari, Beastars and The Apothecary Diaries. He worked at Namco, where he primarily composed soundtracks for video games. Since 2005, he has been affiliated with Keiichi Okabe's music production company Monaca, where he has often collaborated with his colleagues to produce soundtracks for anime and other media.

Kōsaki was born on September 16, 1974, in Toyonaka, Osaka, Japan.^[1] He began playing the piano and Electone, at the age of three. His parents also played classical guitar and frequently played songs by classical guitarists within the household. Although he eventually ceased playing the piano, he played the trumpet in his junior high school's brass band.^[2] He listened to fusion artists such as Casiopea and T-Square, as well as pop artists such as Hikaru Genji, and developed an interest in video game music through the Mycom BASIC Magazine, where he started to program music on a PC-9801.^[3]

As an information engineering student at Kyoto University, he developed an interest in composing music as a member of the amateur circle "Yoshida Music Factory" (吉田音楽製作所, Yoshida Ongaku Seisakusho),^[2] which he decided to join instead of the university's brass club. He purchased a Roland JV-1000 for composition purposes, using a 4-track multitrack recorder. The circle created music in a wide variety of genres, so he listened to several albums for inspiration. Director Yutaka Yamamoto, who was also at the same university, asked Kōsaki to compose the soundtrack for his film Onnen Sentai Ressentiment, as well as playing the role of Emperor Komuro. As he did not have any formal music education, his process for creating music involved listening to existing music and imitating styles, but realized this approach would be risky due to lacking a deep understanding of each genre.^[3]

After his graduation in 1999, he applied to join Namco and submitted a demo tape consisting of tracks he composed while at university, as he admired the music of Namco composer Nobuyoshi Sano and wanted to work with him. After receiving an offer, he joined the company, where his first work was composing music for the arcade game Aqua Rush. He used Microsoft Excel to compose and program the music, which he did not find difficult due to his previous music programming experiences.^[3]

Kōsaki went on to compose tracks for video game series including Tekken and Kotoba no Puzzle,^[2] along with working as an in-house trumpeter for various games. Kotoba no Puzzle: Mojipittan features Shibuya-kei-inspired music, with influences from early Namco game music and 80s synthpop. He aimed to write catchy melodies, which was a trial-and-error process. Its theme song is "Futari no Mojipittan", which features vocals by Moji-kun's voice actress Nana Furuhara.^[4] For his work on Tekken games, he created music in genres such as techno and breakbeat; he did not consider these genres to be his area of expertise, but tried his best to maintain a quality on par with other composers involved.^[3]

During his time at Namco, he was also a member of fellow Namco composer Hiroshi Okubo's doujin circle nanosounds, where he contributed original tracks to a number of albums.^[5] He also participated in J-pop competitions, but was unsuccessful in all of them. Still in contact with director Yamamoto, he would also score the music for the 2005 OVA Munto 2: Beyond the Walls of Time, using the alias Shinji Ikeda as he was still employed at Namco at the time.^[6][7] Citing a desire to compose a greater variety of music without restrictions, he left the company towards the end of the year to join Monaca, a production group founded the previous year by his former colleague Keiichi Okabe, who had previously left Namco in 2001 for similar reasons.^[8][9][3]

Kōsaki's first major project with Monaca was the soundtrack for the 2006 anime television series The Melancholy of Haruhi Suzumiya. Series production director Yamamoto recommended Kōsaki as the composer for the anime, who found it difficult to get involved in such a large scale project outside of Namco, serving as another reason for quitting the company to join Monaca.^[9] An album containing three of his compositions ("God knows...", "Lost my music", and "Koi no Mikuru Densetsu") for the anime sold more than 136,000 copies in Japan and peaked at #5 on the weekly Oricon Singles Chart.^[10] "God knows..." in particular has received a lot of acclaim, although Kōsaki found it challenging to compose due to having little experience with band recording and playing guitar,^[9] so he studied band rock music. Although he often incorporated live musicians in his previous Namco work, this served as the first time he composed a track fully performed by a band.^[3]

In 2007, he composed the soundtrack for the anime television series Lucky Star; the series' opening theme "Motteke! Sailor Fuku" peaked at #2 on the chart upon release.^[11] It would also go on to win the 2007 Radio Kansai Award, a subset of the Animation Kobe Theme Song Award.^[12] He found the workload overwhelming, as prior to joining Monaca he was not used to composing a large number of tracks under time constraints.^[9]

He served as the lead composer for Bakemonogatari in 2009, composing all of the background music and most of the songs. The song "Renai Circulation", features lyrics by Meg Rock and vocals by Kana Hanazawa as character Nadeko Sengoku. Kōsaki felt it would be interesting to feature Hanazawa rapping, inspired by Shibuya-kei group Kaseki Cider. The song received acclaim in particular and inspired a wave of cover dances and mash-ups on Niconico during the 2010s. It later found further popularity on TikTok in the late 2010s, which intrigued Kōsaki as many people who listened to it did not know about it at the time of release.^[13]

In December 2010, he announced an indefinite hiatus from his work due to poor health.^[14] He began a second illness-related hiatus in February 2014^[15] and returned to work in January 2015.^[16] During this time, he re-studied music theory, as he previously felt insecure about not having formal music education.^[13]

In 2019, he worked on the anime Beastars, which features gypsy-inspired music.^[17] In 2020, a compilation album titled Satoru Kosaki 20th Anniversary Selected Works "DAWN" was released to commemorate 20 years of being a composer. It includes a selection of his most successful songs, while the limited edition release also includes a selection of anime BGM.^[18][19] In 2021, he composed for the anime Vivy: Fluorite Eye's Song; the following year, the anime won the Best Music Anime award at AniTrendz's 8th Annual Anime Trending Awards. He aimed to compose powerful songs to correspond with the story and imagery, and has been happy to see his work receive such high praise.^[20]

  Soundtrack composer   Other credits only (e.g. opening/ending themes)

  Soundtrack composer   Other credits only (e.g. performances, insert songs)

• Profile at Monaca (in Japanese)
• Discography at VGMdb
• Satoru Kōsaki at Anime News Network's encyclopedia