According to the 60-year-old, Chongqing hotpot originated around the end of the Qing Dynasty (1644-1911) in the area near Chaotianmen (Gate Facing Heaven). It was one of 17 ancient city gates, and the biggest wharf in the city.

Laborers working at the dock set up stoves to boil leftover animal internal organs, heads and hoofs, along with chili and ginger, both to feed the stomach and fend off the cold. That was the genesis of Chongqing hotpot, or beef tripe hotpot. Soon, some vendors were toting hotpot on poles to sell along the street, a custom that probably lasted for more than a century.

Modern Chongqing hotpot emerged in 1931, according to Mother Chen. A specialized hotpot restaurant took what was on the carrying pole and served it at tables. Customers could then sit down to eat, and there were more choices of dishes and seasonings.

Chen says three generations of her family have sold hotpot; she started to cook it at the age of 12 and spent many years developing her secret recipe of delicious base soup, which is tasty and spicy but mild. It will not give people "excessive heat", symptoms such as dry mouth and blisters on the lips, she says.

Apart from fresh vegetables and meats, Chen brings in most of her ingredients from Chongqing. She says she has not been satisfied with the quality of the options in the local market.

In North China, people are more used to having a warming hotpot in the cold months. But Chen has opened her restaurant in early summer, saying that in Chongqing, people eat hotpot around the year, and she hopes the idea will catch on in the capital.

For people who want the most familiar fare, Bizu Old Hotpot Restaurant offers lamb, beef, mushrooms and vegetables. Some dishes worth trying are pork or beef meatballs with coriander, Shanghai Maling luncheon meat, fresh bamboo shoots and sliced lettuce stems. Dipping sauces include sesame oil with garlic and Beijing sesame paste.