Her work has been widely circulated as Fluxus editions, featured in concert halls, museums, galleries, and non-traditional spaces, as well as being re-performed by other musicians and artists numerous times.
She is best known for her work of the 1960s and early 1970s, especially Spatial Poem, Water Music, Endless Box, and the various instructions in Events & Games, all of which were produced as Fluxus editions.
Members of this collective included Takehisa Kosugi, Shukou Mizuno, Mikio Tojima, and Gen’ichi Tsuge, with Yasunao Tone joining later.
[4] Between 1963 and 1964, she began to compose what she termed "action poems," eliminating musical notation from the score entirely in favor of verbal instructions to be interpreted by the performer.
[6][7] Shiomi further explains that while working on the action poems Mirror Piece and Endless Box in 1963, she made a trip to Tokyo where she was introduced to Nam June Paik by a mutual friend.
[8][6][9] From 1964 to 1965, Shiomi lived in New York City, working closely with George Maciunas and contributing to Fluxus events, editions, and communal life.
Sometime between 1967 and '69 she changed her given name from Chieko to Mieko in accordance with Japanese onomancy (seimei handan), a shift reflected in some of the Fluxus editions from the late 1960s and early 1970s.
[16] Upon her return to Japan, Shiomi reconnected with members of the Japanese avant-garde, and remained active in the Tokyo art and music scene until her marriage in 1970.
Music historian Miki Kaneda has described Shiomi's strategy of this time as a covertly feminist one, aimed at appropriating domestic technologies, such as the postal system, and adapting them toward her performative ends rather than breaking the constricting structures of the patriarchial order that chained her to the home.
[19] She has also experimented more with electronic technology since the 1990s, most notably dealing with telephones and computer synthesized voices in the series of Fluxus Media Operas she produced from 1992 to 2001.
"[14] Toward this end, Group Ongaku hosted performances by artists including John Cage, La Monte Young and George Brecht, and explored the possibilities of objets sonore or sound objects, a key element of Musique concrète.
[21] According to the artist:This explosion of activity [of Group Ongaku] was characteristic of our insatiable desire for new sound materials and new definitions (redefinition) of music itself.
Every week we discovered some new technique [or] method for playing a previously unthought-of 'objet sonor,' and argue endlessly about how to extend its use, and what relationships of sound structure could be created between each performer.
At times we even turned our hands to making music with ordinary objects like tables and chairs, ash trays and a bunch of keys.
[21][22] This strategy was intended to draw attention to the spatial aspects of sound, inciting audiences to understand the constructed environment and thereby "destroy[ing] the hierarchical representation of a musically privileged space.
Art historian Sally Kawamura states that Shiomi was inspired by her rural surroundings to compose works that could be performed in non-traditional settings including the out-of-doors.
This approach grew out of her increasing doubt about the real nature of music, and her growing belief that its essence did not reside in sound waves per se, but rather in sensations of time that could include physical actions.
[27] Shiomi herself now sees the bottled version of Water Music as an exemplary instance of her concept of "transmedia," which she describes an artwork "continu[ing] its creative evolution by transferring from one medium to the next.
"[19] Shiomi launched what would become her best known and most ambitious work just before leaving New York in July 1965 by sending out instructions to a list of addresses George Maciunas kept on file of Fluxus-friendly individuals.
Through this simple conceit, Shiomi created performances that spanned geographic distance and time, addressing her growing concern with the privileging of traditional event dynamics that require everyone to simultaneously meet in the same architecturally delineated space.
[31] Kaneda focuses on how Spatial Poem allowed Shiomi to remain active in Fluxus networks even after marrying and having to run a household in Osaka.