I used see it periodically in fashion-conscious Hong Kong, where a woman in cotton flannels with cartoon characters on them would pop into the neighbourhood 7-11 for something. But most people in the cosmopolitan city wouldn't be caught dead in their jammies.
However in Beijing and Shanghai, this is can be a common sight, and for westerners living here it's a strange observation.
Why do these people do it? Why do they prefer to stroll down the street (sometimes even in their curlers) wearing their sleepwear for all to see?
Finally there is an answer.
Earlier this week, Gao Yubing wrote an article for the New York Times, explaining the phenomenon.
First Gao complains about how Shanghai residents have been warned not to wear their pajamas in public, and there are even volunteer "pajama police" making sure people are properly dressed and if they are caught in their nighties, they will be asked to go home and change.
However, not many people outside of China understand the significance of pajamas.
Pajamas -- not the sexy sleepwear you find at Victoria's secret, but loose-fitting, non-revealing PJs made of cotton or polyester -- have been popular in Shanghai since the late 1970s, when Deng Xiaoping, then China's leader, sought to modernize the economy and society by "opening up" to the outside world. The Chinese adopted Western pajamas without fully understanding their context. Most of us had never had any dedicated sleepwear other than old T-shirts and pants. And we thought pajamas were a symbol of wealth and coolness.
Although they were a kind of status symbol, Gao does explain that as the Chinese are pragmatic people, they don't want to have to change back into their other clothes just to get a snack or something down the street.
Besides, adds Gao, as a retiree told a reporter, "Pajamas are also a type of clothes. It's comfortable and it's not big deal since everyone wears them outside."
It's so refreshing to see Chinese people being so no-nonsense about sleepwear when westerners think it is intimate apparel only found between the covers...