The traditional tangpozi (left) is making a comeback. Photos provided to Shanghai Star

It has acted as a hot water bottle for generations of Shanghainese, and now the tangpozi is making a comeback. Wang Ying reports.

In the time before air conditioners and space heaters, shrewd Shanghainese had their own secret weapon to keep warm on wintry days: Tangpozi (汤婆子).

Every November, as northerly gusty wind sweeps across the city, local families know it's time to take out the tangpozi, a tightly sealed metal kettle full of boiling water to keep the body warm and cozy.

Tangpozi has long been a bedtime item for Shanghai people and others in neighboring provinces to weather the chilly winter. Pouring boiling water into a round tangpozi and using it to warm the bed is a happy childhood memory for generations of Shanghainese.

Tangpozi, also called tangwuzi in local dialect, is made from bronze or tin and flattened into a round ball. The tradition of using tangpozi in China traces back to the Song Dynasty (960-1279). Tang in ancient Chinese means boiling water, and pozi is a joke, referring to the special item’s function as a sleeping mate.

In history, many poems have been written to praise tangpozi. "Spending thousands of jin (money) to buy a jiaopo (tangpozi), a guarantee for sleeping from dusk to dawn," wrote early Song Dynasty poet Huang Tingjian.

In the 1960s, tangpozi were gradually replaced by plastic thermos flasks because of economic concerns.

But to buy a bronze tangpozi remained fashionable for newly-weds during the 1970s and 1980s.