Indanthrene dye immediately won great popularity, and women all over China began to wear qipao dresses of such bright blue cotton fabric. However, only a few of those qipao have survived. The majority of the qipao on show at the exhibition are made of fine silk or lace, and have been well looked after because of their high value. "Mr. Wang has acquired some of these rare Indanthrene qipao, so that we are able to present them in the exhibition," Zhang said. However, the museum being an institution of education and public service, "doesn't consider the price of the objects in our collection, so we can't tell how much money these dresses are worth."

She also pointed out that, as fashion developed in the 1930 and '40s, the cut of qipao became more three-dimensional, optimizing the feminine curves of the wearer's body. "This was also a process of liberation for Chinese women," she said.

Traditional aesthetics demanded Chinese women to hide their sexuality, but since the 1930s, new ideas emerged, encouraging women not to bind their breasts with heavy cloth as scientists of the day pronounced it was bad for women's health, and caused breast feeding problems after giving birth.

Since then, qipao became more about celebrating the natural physical attributes of the wearer, and "Shanghai women became more confident," Zhang said.

The exhibition is taking place at the South Exhibition Hall in the East Wing of the Shanghai History Museum until Oct 16.