[Photo provided to China Daily]

In April The Beijing News quoted the bookshop chain's general manager, Hao Dachao, as saying the Sanlitun outlet was taking 20,000 yuan ($2,900) a day on week days in normal periods and 50,000 yuan a day during weekends and on holiday days, and after beginning to break even was turning a profit.

However, things have not always been that easy. When Sanlian Taofen opened its first 24-hour bookshop in Beijing five years ago, near the National Art Museum of China, it was acclaimed by no less than Premier Li Keqiang, but its second 24-hour shop, which opened near Tsinghua University in 2015, struggled to make its mark and was eventually forced to adopt more orthodox trading hours.

"Location turns out to be key," Jiang Jun, manager of the Sanlitun shop, told China Daily. "Management and operational strategies are also important. A 24-hour bookshop can't survive on government subsidies. We survive on book sales. Takings for things such as food, drink and souvenirs account for just 10 percent of the total.

"In the few years we've been operating, we've been able to see tangible demand for 24-hour bookstores."

Despite some failures, more 24-hour bookshops are sprouting up, located in areas likely to draw high volumes of people, especially those who enjoy nightlife.

They include October Time 24-Hour Bookstore in Zhongguancun, Beijing's technology zone, which caters mainly to university students and those who run startup companies; and Page One, near Tian'anmen Square, which started making one of its three floors available around the clock recently.

"Students and young entrepreneurs are our target customers," says Lin Dayan, an October Time manager. "We offer them a place where they can get in touch with their dreams."

Another 24-hour bookshop in Beijing that allows customers to get in touch with their dreams, and with the past, too, is China Bookstore Yanchi Building, renowned for its collections of ancient books and precious secondhand books. The building in which the shop is located in a restored part of the Di'anmen Gate of old Beijing, dates back to the 15th century.