Ay-Chung Flour-Rice Noodle (阿宗麵線) has sold exactly one dish since 1975: a bowl of thick, gloopy flour-rice noodles in a thin pork-and-bonito broth, topped with braised pork intestine or skipped meat-free, doused in chili oil and garlic. There's no seating — you queue at the counter on Emei Street, get handed a bowl, and eat standing at the ledge outside, which is part of the ritual.
The queue is near-permanent and can run twenty minutes deep at peak times, but it moves fast and the noodles cost only a little more than street snack prices. It's a five-minute walk from the Red House, just off the main pedestrian stretch of Ximending, and it's one of the few places in the district where the line is made up almost entirely of locals rather than tour groups.