Her family has a pickling plant in their hometown in which ingredients are preserved in hundreds of clay jars. Those served with catfish are marinated for at least three years.

Yongjiuwang serves other aquaculture in Sichuan style, including Yangtze long-snout catfish, rock carp and yellow catfish.

Its signature dish is a spicy-soup base, but it also offers a tomato base for guests who can't take the heat.

It also serves such typical Sichuan fare as blood curd in chili sauce, kung pao chicken, mapo tofu, double-cooked pork and hot-and-spicy diced rabbit.

Yongjiuwang also serves homemade sausage made from pigs raised at their own farm in Sichuan.

"The pork we use to make our Sichuan-flavor sausage is from 11-month-old piglets fed only sweet potatoes and corn," Wang Shiyi says.

"I've fallen in love with catering. We're not expanding quickly. But I want to make our restaurant last for more than a century."