Mrs Rupa Sen, by all appearances a regular suburban Bengali homemaker, opens our conversation with a self-deprecating dig, accompanied by a proud smile. “How come all of a sudden the world is interested in my music? I’m like a dead fossil.”

I say something about the power of the internet to create new audiences and connect people in unexpected ways, especially for music obsessives like me. But it is a fair question. Why, almost 40 years after its release, is the nerdy world of music collectors paying so much attention to a homemade record made on the spur of the moment in the Canadian prairie town of Calgary?

The record may be just four tracks long and released on an obscure German label (Ovular), but it has an ambitious title: Disco Jazz. Arguably, no work of art since Tolstoy’s War and Peace has branded itself with quite as much chutzpah. Bursting with the energy synonymous with disco but nuanced with long jazzy instrumental segments and sophisticated drum breaks, the music does manage to both intrigue the mind and get the body moving.

Since its re-release in 2017, Disco Jazz has been hailed by critics as a “Holy Grail”, and as “Essential” and “Unmissable”. It has featured on music-snob websites such as Boomkat and was released – yet again – on March 29 by the respected Chicago-based archival music company Numero Group. Hugely successful, it sold out worldwide, and another release date will be announced soon. Original copies of the LP have fetched hundreds of dollars.

What’s going on? Why all the fuss? What’s the story behind this rediscovered “transcendent” “Indian gem” of global popular music?

After hearing the record, I wanted to know what happened to the creator whose face beamed so brilliantly from the cover. Was she alive? What happened after the record was released? Was she still singing? Several months went by before someone contacted me to say exactly what I wanted to hear: Sen was alive and well. And she lived in Kolkata.

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Musical journey

When the Skype camera flickered on, Rupa Sen nee Biswas greeted me with a namaskar and that infectious smile. She was accompanied by her son, Debayan, and niece, Anneka, to help out, if necessary, to bridge the language gap.

Sen grew up a typical middle-class, but “quite liberal”, Bengali girl in 1970s Calcutta. There was music in the family. “My mother, Sabita, was my first guru, and she taught me how to sing classical music,” said Sen. But the 1970s generation was looking beyond India’s shores for its music to the likes of The Beatles and Tom Jones. And of course, the voices of Asha Bhonsle and Lata Mangeshkar were everywhere. “My dream was to sing playback,” said Sen.

She performed in small shows around town, but in an era before multiple television channels, FM radio and YouTube, there was only one way to reach a large audience – All India Radio. Sen approached the Calcutta station of the broadcaster in 1978 and auditioned. “I wasn’t successful the first time, but I tried again,” she said. “After a second audition, AIR broadcasted me singing a pop song.”

Uncertain about a career in pop, Sen took admission in Calcutta University and began to study biology. She continued to sing “here and there”, until a family holiday to Canada finally cracked the music world open for her.

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“In August 1981, we went to visit my elder brother, Tilak Kumar Biswas, in Calgary,” said Sen. “My brother had already told everyone there about my singing career, so I had to give a small performance in his house on the day of our arrival.” Some members of the local Indian community were also invited. “So impressed” were the audience members with her singing that they asked her “to do a public show”.

A few days later, Boris Roubikane Hall at the University of Calgary was booked for a Geet and Ghazal live show. Around 1,000 people came, including the boundary-pushing sarod player and son of Ali Akbar Khan, Aashish Khan. Sen sang for three and a half hours that evening, and Khan was thrilled enough to approach her brother. “My brother and Aashish had known each other for a long time and were good friends,” she said. “After a few days, Aashish came over to my brother’s place and we started having jam sessions together. We even played together on local TV. It was after that show that Aashish proposed to my family that he would like to make a recording.”

Given that time was of the essence – the Biswas family was to head off to England for the second leg of their summer holiday in a week – Khan gathered together a group of local studio musicians at drummer and producer Richard Harrow’s home studio, which was known as the Living Room. There, in the studio, were Harrow and a local Calgary guitarist and student of Khan’s, Don Pope. Pope, who had nurtured an interest in Indian classical music from his teenage years, would embark on a tour of India the following year as part of Khan’s fusion outfit the Third Eye Band. There was no question then that he would support his guru in this impromptu recording event.

Over the next week, Sen went to the studio for three-four hours every day and sang lyrics composed by Khan’s wife Saroj. The lyrics were not complex, but like the opening track of Disco Jazz, Moja Bhari Moja (Fun, Great Fun), they fit the spirit of the times, which was all about dancing and enjoyment.

Disco Jazz is anything but your usual 1980s disco record. It manages to use the form, sounds and structures of club dance music to reach another level, which, even if not exactly jazz, is something entirely its own form.

Although belonging to a much-maligned genre, the musicianship on Disco Jazz was remarkable. It’s not hard to see why critics swoon over the record. Fast-paced drum beats and funky bass keep the bottom end firmly in place and create a wide space for Pope’s guitar – by turns hypnotically rhythmic and blistering – and the inevitable waves and swirlings of the synthesiser. Pranesh Khan, Aashish’s brother, fills in the gaps with some fine tabla beats. But the clear instrumental hero here is Khan’s sarod, electrified and amped up for this special occasion. It is this unexpected and exotic sound that makes the songs so unlike the other disco music of the time. That and the fact they are sung in Bengali.

Soaring over all the fast moving musical traffic, Sen’s voice sparkles and glides – she is equally adept at scatting as she is at singing or even pouting coquettishly. The thing that stands out, though, is what a natural she is in the studio. Small live concerts in your hometown are one thing. But it’s as if finding herself in a studio surrounded by crack musicians, Sen shed her inhibitions and stepped into her destiny.

“This was my first time in a studio but I was so excited,” recalled Sen. “We recorded everything live.” There was even an appearance on Calgary TV. Were you nervous? “No. I was enjoying the attention. To be there with Khansahib and Don Pope. It was amazing.”

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The recording over, Sen packed her bags and flew to the UK to visit other family members. Though the experience had been thrilling and all too short, “all the musicians became friends and have visited me in India over the years”.

Following the recording, Sen’s two brothers funded the production of the LP and in October 1982, the record was released in India. “It was in the shops in Calcutta, but…”

But what?

“Around the same time, Nazia Hassan’s record was released,” said Sen. The young Pakistani singer from Karachi had become a pan-Asian sensation after debuting in Feroz Khan’s Hindi film Qurbani in 1980. By the time Sen’s Disco Jazz came out, Hassan and her brother were flying high not just in the subcontinent but across Asia and the UK as well. Legend has it that the siblings’ Disco Deewane sold around one lakh copies in Bombay alone soon after its release.

Given the lack of hype and the absence of a major label, Disco Jazz struggled to get much airplay. “It was so exciting to see the record in the shops, but sadly the Nazia craze made it hard,” said Sen. While she sang several “songs around Calcutta in various shows”, such as Ke jeno aakashe rong e rong tuli diya (As if someone has added colours to the sky with a brush) – the music and lyrics “by Sudhin Dasgupta, who was my guru” – and Aami jodi hotam mago vhor belakar phakhi (Mother, if I were a morning bird) her time in the limelight was to be delayed by several decades.

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Sen considers the recent attention her little record is garnering with mixed feelings. As someone who admittedly “likes the attention”, she is chuffed that her record is reaching new audiences. She has set up pages on Facebook and other social media platforms. “But no one has asked my permission to release the record,” she said. “I’ve not received even one rupee from any of these companies, even though it is my name, my picture and my voice on the record.”

With dreams of stardom and singing professionally seemingly unrealised, Sen embraced the life that was available. But there are no traces of regret or bitterness. “I believe my life is like a coin,” she said. “Rupa Biswas is just one side. On the other side are other things that are also important and good.” Over the years, Sen has been a music and beauty columnist for Aajkal newspaper, tutored students in math and science, raised a family and taken up painting, gardening and embroidery. “And I still sing.”