With the Yellow Magic Orchestra, he inspired the sound of hip-hop, electro and techno. Then, the Japanese composer won an Oscar and worked many of the greats, including Davids Bowie and Byrne. Now, in recovery from cancer, his impulse to innovate is as strong as ever

On the roof of a half-built tower block overlooking Oslo’s harbour, Ryuichi Sakamoto – former global pop star, a godfather of techno and hip-hop and an Oscar-winning composer – is in a makeshift plastic shack, coaxing microscopic scratches and scrapes out of a cello, then turning them into huge tonal washes with his laptop. As the sun sets, artificial mist billows through the crowd, floodlights suspended from the construction site’s cranes swing above us and the lithe dancer Min Tanaka strikes alarming poses on the parapet of the building, disappearing in and out of the fake clouds.

This performance for the city’s Ultima festival, a collaboration with “fog sculptor” Fujiko Nakaya, is profoundly moving: elegant, nuanced, emotional, rich with cultures from across the globe. Themes of ageing and mortality emerge as Tanaka disappears into the mist; he is 72, Nakaya is 84 and Sakamoto is 65 and in recovery from the throat cancer he was diagnosed with in 2014. These themes also appear throughout the 2017 album, Async, Sakamoto’s first solo effort in seven years. Heralded as one of the year’s electronic highlights, it is now bolstered by Async Remodels, a set of remixes by the cream of the avant garde, including the Björk collaborator Arca and Oneohtrix Point Never.

Talking to Sakamoto in a cafe before the show, his natural urbanity is made calmer still because he speaks slowly and quietly, so as not to irritate his throat. He slips from the mundane to the deathly serious with gentle humour. “I was aware of that theme of mortality in my music since around 2009,” he says. “The decaying and the disappearance of the piano sound is very much symbolic of life and mortality. It’s not sad. I just meditate about it.”

Sakamoto grew up immersed in the arts. His father was an editor for the novelists Kenzaburō Ōe and Yukio Mishima. “So all the time all these very young wannabe writers and novelists came to the house and there was a lot of drinking until the morning, and lots of books in the house, which we had to avoid so the piles didn’t collapse on us. Very cultural!” He went to “one of the most liberal, conceptual” infant schools in Japan, which Yoko Ono had also attended, and was exposed to art and classical music there, painting and taking piano lessons from the age of six.

Facebook Twitter Pinterest Sakamoto on stage in 1988. Photograph: Ebet Roberts/Redferns

A nebulous idea of western culture also fascinated him. He remembers American GIs as an intriguing presence on the streets of Tokyo, and at 11 he fell hard for the Beatles and Rolling Stones. “I didn’t know if they were British or American, just western,” he says. “But I loved them. I had the pop music on one side and Bach and Haydn on the other, but then, when I was 13, Debussy came into my ear. Music about a mood and atmosphere, and not east or west. Asian music influenced Debussy who influenced me – it’s all a huge circle.”

By the time he got to university to study music composition (“Boulez, Stockhausen, Ligeti, Xenakis”), Sakamoto was in demand. He played with free jazz bands, then in 1972 met the folk-rock singer Masato Tomobe “in a tiny, tiny bar in Shinjuku [Tokyo]” who took him on tour as his keyboard player. “I was working with the computer at university and playing jazz in the daytime, buying west coast psychedelic and early Kraftwerk records in the afternoon, and playing folk at night,” he says. “I was quite busy!” From this tour came industry contacts, a thriving career as a session player, and the chance to mingle with musicians such as Yukihiro Takahashi and Haruomi Hosono, who in 1978 formed the electropop band Yellow Magic Orchestra (YMO).

“It was considered a privilege to be called to join Hosono’s sessions,” Sakamoto says. “We found out later that this was a kind of audition for forming Yellow Magic Orchestra. Soon after this session, I was called to his house in Tokyo. We were shown a drawing by Hosono himself – it was of Mount Fuji erupting, and it said ‘FIVE MILLION SALES’. His dream was creating independent music and exporting it to the world from Japan. I liked the idea, so I said OK.”

Facebook Twitter Pinterest Sakamoto and David Bowie in Merry Christmas, Mr Lawrence. Photograph: Allstar/Universal/Sportsphoto Ltd

That humour and ambition would drive YMO’s techno-pop to huge worldwide sales, particularly in the US where they mischievously played on tropes of the “mysterious east” and early Reagan-era fears of a Japanese economic takeover, while dressed in Mao-style boiler suits or garish, cyborg-like new wave fashions. The members’ solo tracks also gained a large black audience; they appeared on Soul Train and inspired early hip-hop, electro and techno. Sakamoto still shakes his head as he recalls Afrika Bambaataa telling him: “Kraftwerk and YMO made hip-hop.” Uncharacteristically, he falters, searching for the right word. “I was … grateful.”

But Sakamoto didn’t like stardom. The irony and costumes, he admits, were a shield against attention, and he would be far happier one step removed from the limelight.

Asian music influenced Debussy, who influenced me – it’s all a huge circle

He managed this retreat better than most. His music remained at the heart of the mainstream, particularly via his soundtrack work. After Merry Christmas, Mr Lawrence, in which he also acted alongside David Bowie, he won an Oscar for the soundtrack of The Last Emperor, beginning a long relationship with Bernardo Bertolucci. He worked with David Byrne, Iggy Pop, Bootsy Collins, Brian Wilson and, most enduringly, with David Sylvian. But avant garde instincts kept pulling him away from the mainstream, and his 21st-century output has tended towards ambience and abstraction, whether on projects for tiny electronica labels or the Golden Globe-nominated score for The Revenant, made with regular collaborator Carsten Nicolai, AKA Alva Noto.

All of which, seemingly, has left him with an undimmed creative urge. Even during his cancer treatment, he managed to make stunning ambient records with Taylor Deupree and work on Plankton, an installation in museums in Paris and Kyoto combining art and science. As well as Async and its Remodels, and the Ultima festival piece, this year has also seen the release of two new soundtracks to Korean films.

He seems sanguine about mortality – much of his conversation echoes Async’s poetic sample from Bertolucci’s adaptation of Paul Bowles’s The Sheltering Sky: “How many more times will you watch the full moon rise? Perhaps 20, and yet it all seems limitless.” He only expresses anything resembling frustration at his tiredness and inability to fit as much as he would like into the year. That and the fact that he failed to reconnect with Bowie when they were both living in downtown New York: “My great regret.”

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Still, life is good. He has a normal existence in New York, watching Family Guy, Curb Your Enthusiasm and Korean films; making coffee, playing Bach on his piano and reading widely – especially the anthropology and ethnomusicology that has always informed his music, as well as archaeology and palaeontology, which he would have studied at university had music not taken over. And for all his tiredness, he is excited by the young talent gathered for Async Remodels and has developed close relationships with the more established remixers: “I’ve been deeply impressed by Oneohtrix Point Never for years and Jóhann Jóhannsson is a very good friend of mine – I would love to collaborate with them in the future.”

And where his last decade of music has been built on ambient tones that fade and dissipate into the electronic ether, now, he says: “I have a longing for violin or organ. Is it too simple to say those sustaining sounds symbolise immortality?”

Async is out now on Milan; Async Remodels is released on 23 February, with digital versions out now. Glass by Alva Noto and Ryuichi Sakamoto is released on 16 February on Noton.