There's no review for this although it's available on 4K and it's easy to see why. It's less a documentary than a celebration of the late 1970s folk revival which was born out of the demise of the Japanese student protest movement that had heavily influenced independent film making, and therefore highly recommended for Japanologists and other Nipponica aficionados.
Director Kai Satô was ill-fated Sadao Yamanaka's nephew, who was drafted into the army for making the gloomy social drama "Humanity and Paper Balloons" (1937), resulting in his death from dysentery. That made him a "leftist by association" and impaired his career. He went through many apprenticeships and was assistant director to Kurosawa's "Rashomon", going on to direct many yakuza films for Shochiku. He did not attach himself to the Art Theater Guild founded by Nagisa Oshima as a protest against studio conventions as he was already in his 50s. Only in this work, his second-to-last, he combined the lavish sets of yakuza epics (evoked by Tarantino in "Kill Bill") with an art house observatory approach to the youths forming the Ondekoza, a collective practicing Taiko and Shakuhachi on remote Sado island while undergoing rigid physical exercise.
While there is some information on the participants, the film doesn't really provide much information what motivates the members of Ondekoza, which is regrettable because it was made during the rift of its leaders. They split up into Kodo, who still reside on Sado and organize workshops and an annual Earth Festival, and Ondekoza, who moved to the mainland and focused on performances rather than the collective. It still exists today but mainly as a brand, while Kodo is firmly rooted in the island culture the film references, so Kodo is more representative of what the film portrays.
The experimental soundtrack using computer cadences over drums won't be pleasant for drumming enthusiasts, and there is an undeniably gay aesthetic in the underneath shots of the drummers' crotches and oiled-up limbs while wearing nothing but loincloths (Ondekoza adopted this upon a suggestion by fashion designer Pierre Cardin). This prompted the studio to shelve it and it was never theatrically released. That's why it has remained obscure, although it is visually opulent and was Satô's own favorite work, the only one in which he could fulfill his vision.
