Every day, she buys vegetables at a market at 3 am before heading to another market to buy meat.

She once had to visit markets six times in one day to get everything.

"My father told me that I have to first know every ingredient," she says.

"So, I spent eight years buying them every morning to become familiar with them."

Wang Shiyi took the chance when Yongjiuwang was again invited to open a Beijing branch last year. She decided to source all of the ingredients from Sichuan to ensure the flavors were the same as back home.

Tuojiang yanian catfish, for instance, are distinctive from other varieties in that they have larger mouths and survive only in clear water.

"They eat fingerlings. So, we feed them live fish so that their meat is fresh and tender," she says. The catfish are ordered two days in advance and are, like most ingredients - including ginger, garlic and pickles - transported from Yuxi to Beijing via Chengdu's airport daily.