Actress Zhao Liying wears a du dou in the 2013 film The Palace. [Photo/Mtime]

A gift of love

There are no reliable historical records regarding the origin of the du dou. Yet a similar type of clothing called ri fu was mentioned in Zuo Zhuan, the earliest annals in China.

It was about a woman, Xia Ji, who had an affair with a king and the king's two secretaries. The woman sent her ri fu as a gift to the king to show her love. The king was thrilled and wore her underwear all the time. One day, he showed the underwear off to his two secretaries. He didn't expect that the latter two also took off their clothes and revealed ri fu that Xia Ji had sent to them.

The affair was recorded in the annals to criticize the shamelessness of the king. Yet it also implies underwear was a secret gift between lovers.

Many folk tales in the Yuan, Ming and Qing dynasties (1271-1911) have similar plots about lovers exchanging their du dou.

In Yu Shi Ming Yan, edited by litterateur Feng Menglong from the Ming Dynasty (1368-1644), there is a story about a du dou called "pearl underwear". A woman also sent the underwear to her lover as a token, for they could not meet every day.