Dr Kiku Day (PhD, London; MFA, Mills; BA, London) is a shakuhachi player and ethnomusicologist from Copenhagen Denmark with Japanese-American background.

Kiku studied honkyoku with Okuda Atsuya in Tokyo for 11 years before she returned to Europe to study ethnomusicology. She has her BA Honours and PhD from SOAS, MFA in Performance from Mills College, USA focusing on playing contemporary music and improvisation on the shakuhachi. She has worked as external staff at SOAS and Goldsmiths, University of London, Aarhus University, and Royal Academy of Music, Aarhus, Denmark. 

Day is active as a performer and has performed at venues such as Carnegie Hall, Royal Festival Hall, Disney Hall, and Danish Radio Concert Hall. 

Day is known for her innovative playing techniques in cross-cultural settings, especially in her collaborations with performers such as Hyelim Kim from South Korea and in Sonas Mutua – a duet with Marisol Jimenez from Mexico. 

Day has since her return to Europe dedicated her life to the potential use and creation of a contemporary repertoire for the jinashi shakuhachi. Several composers from different parts of the world have written for her, among others: Roxanna Panufnik (UK), Takahashi Yūji (JP), Frank Denyer (UK), Vytautas Germanavicius (LT), Mogens Christensen (DK), Marisol Jimenez (MX) and Yumi Hara (JP). Composers such as Arnannguaq Gerstrøm (GL) and Jexper Holmen are currently composing for her.

Day is a founding member and served 10 years as chairperson for the European Shakuhachi Society and served as the chair of the Executive Committee for the 7th World Shakuhachi Festival Goldsmiths, University of London and the one-day academic conference Shakuhachi Symposium held at SOAS, University of London.