My guides led me into one of them, Hau Soi Chaiyen—a family business that's been serving kao soi for some thirty years. A pretty girl of 18, named Comtan, showed us how the soup is assembled, and taught me that kao soi comes in more than just a single form: She dipped a strainer full of noodles into a pot of hot broth and then dumped them into a bowl. Over this she ladled a stew of chicken meat and scallions, then asked which broth I wanted—nam kathi, which was the curried coconut-milk broth that I had tasted in Chiang Mai and Chiang Rai, or nam nyo, a spicy pork broth. "One of each" is what I actually felt like saying, but I thought that might be a bit rude, so I opted instead for the pork version. Over the top of the bowl, Comtan sprinkled fried noodles. The condiments this time included pork rinds, salty fish sauce and plum sauce, limes, chopped chiles and onions, bean sprouts, and kimchi-like pickled cabbage. We washed down the meal with several bottles of Polaris water.