Only cold noodles can beat major heat

"When the noodles are taken out of the pot, they are extremely hot," Jin said. "The first rinse removes the heat, while the second cools the noodles completely."

The noodles must also be rubbed and washed to remove the stickiness caused by the sweet potato starch. The low temperature helps them tighten and retain their signature chewy texture — one reason diners need scissors to cut them.

Yet the defining element of a good bowl of cold noodles is the broth. "It's the most important part," Jin said. At his restaurant, the beef is soaked in running water for up to a day and a night to remove impurities. It is then blanched and simmered for about five hours with carrots, scallions, onions, ginger, licorice root and red dates.

"This step may not appear important, but it matters greatly to us," Jin said of soaking the beef. "It determines whether the broth has a clean taste."

After settling for 48 hours, the concentrated broth is seasoned with sugar and vinegar, then frozen into fine ice crystals to keep it cold without diluting its flavor.

The recipe also reflects traditional ideas about balancing ingredients. "Buckwheat is considered a cooling food, while beef is relatively warming," Jin said. "Beef broth is used to provide balance."

Many locals eat the egg first in the belief that it helps prepare the stomach for the cold soup. Each bowl is topped with pickled cabbage, cucumber, half a boiled egg, beef and seasonal fruit. Watermelon often appears in summer.

Even the flavor changes with the seasons. "We make the broth more sour in summer, because it is more refreshing and helps relieve the heat," Jin said. "In winter, we make it sweeter so it feels gentler on the stomach."

For Xu Shunji, who has operated her cold noodle restaurant for 20 years, every detail matters.

"The noodles, pickles, sauce and broth must all come together properly. If one part is not right, the cold noodles will not taste good," Xu said.

She is particularly proud of the locally raised cattle. "Yanbian yellow cattle make the broth especially fragrant and rich. Other kinds of beef do not produce quite the same flavor."

In Yanji, cold noodles are often paired with guobaorou, crispy sweet-and-sour pork. Some diners dip the freshly fried pork into the icy broth, cooling its crisp coating while adding another layer of acidity and sweetness.