Kosi was married to Elwin for 10 years
She is a wizened octogenarian tribal widow who lives in penury in a thatched hut in a village in the central Indian state of Madhya Pradesh.
Nothing unusual about that in India's teeming villages, but Kosi was once married to pioneering British anthropologist Verrier Elwin.
Elwin studied little-known Indian tribes and wrote extensively on Indian tribal life, art and culture. He was close to Mahatma Gandhi and Jawaharlal Nehru.
The Oxford-educated Elwin came to India in 1927, and stayed on here until his death in 1964.
Kosi and Elwin were married on 4 April 1940 - she was 13 and he was 37. A decade later, they divorced.
Elwin took another wife soon after and died in Delhi.
Living on memories
Today, Kosi, a member of the Gond tribe, has little money and no land, and is so ill that she cannot walk - she squats on her mud floor and uses her hands to move.
These days, she survives on her memories of life with Elwin, English tuition in Bombay (now Mumbai) and meeting Gandhi and Nehru.
Sitting in her hut in the village of Raythwar in Dindori district in Madhya Pradesh, Kosi's eyes light up as she talks about how she met Elwin for the first time when she was walking to a primary school which he had set up.
"He was very fair and tall. He used to crack jokes a lot. He had blue eyes," she says. "It was Elwin who began calling me Kosi. My original name was Kaushalaya."
Within days of their first meeting, a messenger reached Kosi's parents - Elwin, fondly called 'bade bhai' (big brother) in the village, had proposed.
Verrier Elwin was a pioneering anthropologist
It did not matter that Kosi did not know a word of English except 'get out'; Elwin, on the other hand, had been in India for 12 years already, and lived and ate very much like Gonds and spoke the local dialect.
It also did not matter that Kosi's family were poor - Elwin described them once as "decaying baronets in a PG Wodehouse story".
But Elwin failed to convince Kosi's parents, who found it difficult to accept their daughter's marriage outside their own caste.
"So Verrier resorted to what he termed 'love marriage by capture' - he got married under the Special Marriages Act, designed for such inter-religious and inter-racial unions, followed by a four-day Gond wedding," writes Elwin's biographer, Ram Guha.
After their marriage, the couple began living in a colonial bungalow in Jabalpur, where there were dozens of servants at Kosi's beck and call.
Dinner with Nehru
In those days, Kosi says she was known as a "raging, roaring girl not in the least in awe of her husband" and a gifted singer and dancer.
Sitting in her hut, she still remembers her visit to Bombay with Elwin, staying at the best hotel, going to the cinema to watch English movies and meetings with Jawaharlal Nehru.
"We had gone for dinner with Nehru. When he came to know that I was in the family way, he told me to name the child, if it was a son, after him," she says.
In 1941, Kosi gave birth to a son and named him Jawahar Singh.
Jawahar, a motor mechanic, died some time ago of an untreated ulcer. The couple's second son, Vijay, also died young.
Kosi lives alone with her memories of Elwin
There are accounts of Kosi sitting next to Krishna Hutheesingh, Nehru's younger sister, dressed in a cotton sari with silver amulets on her arms and a belt hanging from her waist, at a reception in Bombay.
Ram Guha quotes a local journalist who met her in Bombay and marvelled at the "calm dignity with which Kosi, whose life hitherto had been spent in a tiny mud hut in a remote village, rose to her new experiences" in the city.
"All the gloomy prophecies that my marriage would mean social death were falsified," Elwin wrote to a friend.
Today, the ageing widow seems to be unaware of Elwin's stellar scholarly achievements.
"He was always writing books. And he did not brook any disturbance when he was at work," says Kosi.
After India's independence in 1947, Elwin took Indian nationality and Nehru appointed him as an adviser on tribal affairs for north-eastern India.
He moved to the north-eastern hill town of Shillong, divorced Kosi and remarried.
"He suddenly went away. And he never came back," she says.
Kosi says Elwin would initially send 25 rupees (now 55 US cents) every month to keep her family going, but that "stopped very soon".
Kosi says Elwin "went away suddenly"
She took to working in the farms to keep the home fires burning.
Ram Guha says the memory of the divorce was "so wounding that Elwin could not bring himself to write about his first wife in his autobiography, where Kosi and the years of their marriage are disposed of in two paragraphs".
"I cannot even look back on this period of life without a deep sense of pain and failure - indeed I can hardly bear to write about it," Elwin wrote.
Kosi, however, does not indulge in any blame game - the romance between a teenage tribal girl and a British scholar was clearly doomed.
And in her shanty in Madhya Pradesh, the forgotten Kosi Elwin awaits death.