Ainu upopo is the sitting-song group vocal tradition of the Ainu peoples of Hokkaido, Sakhalin, and the Kurils, historically carried primarily by women. Performance sits three to eight singers in a circle around an inverted nima (pot lid or bucket) struck with the palm for rhythm; a lead singer starts a short phrase, and successive singers pick it up one to two beats behind, producing a circular canon. Tempo is moderate, the melodic line uses a three-to-five-note restricted scale, and lyric content addresses kamuy (spirits), work memory, and playful language. The already-catalogued 'ainu-music' slug covers Ainu music comprehensively (sitting-song upopo + dancing-song rimse + spirit-narrative kamuy-yukar + heroic-narrative yukar + the OKI-era tonkori revival); this entry narrows focus to the upopo women's-song sub-tradition and its female-line transmission.

The Ainu are Indigenous peoples of northern Japan (Hokkaido, Sakhalin, Kuril Islands), historically hunter-gatherers whose group song was integral to both communal ritual and daily labour. Upopo is women's circle-song in its native form, arising naturally in domestic labour (food preparation, childcare) and then extended into ceremonial contexts. Twentieth-century Japanese assimilation policy caused rapid loss of Ainu-language speakers, and upopo transmission concentrated among a small number of elder carriers. Chikappu Mieko's Chitose-city work, Umeko Ando's (1932–2004, mother of OKI Kano) Biratori household transmission — these bridged the tradition through the mid-twentieth-century crisis.

First, the circle-canon structure. The lead sings a two-to-four-beat phrase; the next singer picks it up one to two beats late, then the next later still — the layering is neither unison nor Western harmony but a form-specific 'canon-that-is-simultaneously-percussive.' The inverted nima's low thud provides the rhythmic bass, and the three-to-five-note melody sits atop. Umeko Ando's 'Ihunke' (2001, Tonkori Records) separates these layers cleanly — her weathered voice paired with a younger-generation instrumental accompaniment audibly encoding inter-generational transmission. Marewrew (formed 2003) renders the circle canon in four contemporary female voices.

Start with Umeko Ando's 'Ihunke' (2001, Tonkori Records) — the traditional-carrier canonical recording, transparent aged voice against her son OKI Kano's arranged instrumental backing. Then Marewrew's 2010s+ albums (also Tonkori Records) for the contemporary female-quartet re-composition of the circle canon. Academic references: Kindaichi Kyosuke's 1920s–30s recordings held at Hokkaido University Library, and Chiri Yukie's 'Ainu Shin'yoshu' (1923, Iwanami paperback edition) as background reading into the poetic world.

'Upopo' is an Ainu word specifically meaning 'sitting song,' contrasted with 'rimse' (dancing song). The circle-canon form is common to Northeast Asian hunter-gatherer group song and shares systematic continuity with the vocal traditions of the Nivkh and Uilta on Sakhalin. Umeko Ando was the mother of OKI Kano (of OKI Dub Ainu Band); her late-life 'Ihunke' recording literalises the practice of intergenerational transmission — the son recording the mother. Marewrew's four members (Mayunkiki, Rekpo, Hisae, Mika) all publicly identify as Ainu carriers, positioning their work as 'continuation' rather than 'revival.'