Four years ago, Dr Samuel Wong went in search of "the Chinese music of Singapore's forefathers".

Wong, a pipa player and the co-founder of arts group The Teng Company, stumbled upon an underground community of musicians hidden away in Singapore's dialect associations.

Many were in their 70s or older; some drove taxis by day. On weekend afternoons, they gathered in shophouses with century-old instruments and jammed.

Nobody listened to them. Sometimes they got bookings from temples and then they would play for the gods.

Wong's desire to honour and preserve the work of these Chinese music pioneers gave rise to the Forefathers Project, which began as a research process and has since bloomed into a documentary series, released on the Facebook page of The Teng Ensemble, the performing arm of The Teng Company, and a concert, Heirlooms, which will be held at the Esplanade Concert Hall on Friday.

The company has commissioned eight new works using these folk instruments, such as the nanpa, the gaohu and the qinqin. Some, like the Teochew pipa, had to be custom-made for the concert.

"A tradition is never stagnant," says Dr Wong, 36, who has a PhD in ethnomusicology. "It is always alive. We started asking ourselves, how can we reinvent this tradition so that it becomes more palatable for a younger audience?"

The project began when he went in search of Mr Yeo How Jiang, who started Singapore's first Chinese orchestra in 1959, a man so unsung that although Dr Wong had written about him in his thesis, he did not even know he was still alive.

When he finally found him, Mr Yeo was playing in the Thau Yong Amateur Musical Association, which performs Teochew music and Waijiang, a near-extinct form of music that dates back to the Qing Dynasty. It was all but wiped out in China during the Cultural Revolution, surviving only in the diaspora.

Dr Wong spent a year playing with Thau Yong - the only way he could learn their style, because they did not use scores, wrote nothing down and improvised perpetually. It was worlds away from his own conservatory training and the Chinese orchestral tradition, which most people are familiar with.

"What I found out was that all of them held a root melody in their heart," he says. "And then they let go of it and played everything but that root melody. I had never heard anything like it before.

"They were actually innovating with the music. It was not stagnant. They were finding new ways of performing and some had even invented their own instruments."

Over the years, The Teng Company created a series of videos chronicling migrant folk music from the Hokkien, Cantonese and Teochew traditions, working with groups such as Thau Yong and Siong Leng Musical Association, as well as traditional luthiers and retailers.

Halfway through the project in 2017, Mr Yeo died at the age of 89. The footage the company took of him is one of the final recordings of his work.

"I could not do what he did," says Dr Wong. "He had done this for 80 years, it was in his blood. What I could do was preserve these kinds of music and empower these small associations."

Mr Jeffrey Eng, the third-generation owner of Eng Tiang Huat Chinese Cultural Shop, was among those interviewed for the documentary. Eng Tiang Huat, opened by his grandfather in the 1930s, was a pioneer in retailing Chinese instruments in Singapore, but he predicts it will end with him as his children are disinclined to take over.

The 58-year-old, who helped to restore and customise some of the instruments for the concert, called the Forefathers Project a "very timely" initiative. "They are coming in at this time when all the pioneers are disappearing. I am grateful they managed to capture some of it before Mr Yeo left."

He hopes that Singapore, with its unique position between East and West, can be a research centre for Chinese music pedagogy. There is a dearth of quality English translations of literature on Chinese music, he notes.

Dr Wong plans to expand the project by producing music videos and even perhaps taking the concert on a world tour.

"Why can't the world know this is Singapore's music? I want people to know that Singapore is culturally rich and all we need to do is look into our past to make sense of our present."