Ca tru singing grew out of folk festivals in the countryside where dao nuong, female artists, would ply their trade. The troupe comprised two or three singers with a male musician, and they would take it in turns to sing through the night at festivals.

By the late 19th and early 20th century, this form of singing had moved from the country to the city.

In Ha Noi, Hang Giay and Hue city streets resounded with the beautiful melody of these astounding voices.

But the owners of the theatres could not always afford the purest ca tru voices, so they made do with a couple of professional singers.

To keep their customers interested, the owners hired some “ornamentation” in the form of pretty young girls to serve the wine.

These girls, called dao ruou, needed no particular skills – they just had to be beautiful and polite to the many customers.

But the life of a dao ruou was not a happy one. Many of the girls were cheated into the trade, or else enslaved by debt and forced to work their youth away in these makeshift bars.

The men who owned these bars were often criminals, at best they were gamblers or loan sharks. The girls were often forced to work as prostitutes, they changed their names and left any hope of a normal life behind them.

The luckier among them married Chinese exiles in the city, but they were always considered second class citizens.

Ha Noi’s Nga Tu So, Vinh Ho, Van Thai and Lang streets were bustling with people drinking alcohol and chatting against the backdrop of ca tru singing at theatres.

Kham Thien Street was also a famous hangout. The theatres were all thronging when pay day rolled around. But the posterity didn’t filter down to the dao ruou, who were still trapped by their debts.

So it was that Quach Thi Ho became a shining light in an otherwise dimly-lit profession.

She joined a ca tru troupe in her home province of Hung Yen at the age of seven. By the 1930s, at the tender age of 20, she was already a famous singer.

Ho worked at the Van Thai Theatre for 24 years, where she amassed a loyal following and fortunately earn enough money to live a comfortable life and engage in charitable works.

In 1945, after the August Revolution, Ho helped to waive the debts of all the dao ruou workers in her theatre – effectively buying their freedom.

The ca tru theatres disappeared from view, but the beautiful art suffered a hangover: its image tainted by memories of its seedy past.

Many people couldn’t break the association of this beautiful music with prostitution and vice, but singers like Ho worked hard to clean up its reputation and convince audiences of its worth.

Nowadays, the seedy past is all but forgotten and people recognize ca tru singing as a pure and classical art form.

Ho has won plaudits for her golden voice. In 1976, she took out the first prize at the Teheran International Music Festival and then performed in a number of countries.

Even recently, at the age of 80, she has appeared on Vietnamese television and fans thought her voice as sparkling as ever.

Ca tru favorites based on poems by much-loved ancient authors such as Chinese Du Fu and Bai Juyi are still popular.

And a rousing rendition of poems like Thu Hung (Inspiration of Autumn) and Ty Ba Hanh, Dao Hong, Dao Tuyet (Singer Hong, Singer Tuyet) can still stir a Vietnamese soul.