What this section covers. Asian food in Mexico City — which has two quite different histories running in parallel.
The old one. Chinese migration arrived in the late nineteenth century, and the city still has a small Barrio Chino on Dolores, a block from the Alameda: a handful of restaurants, a lion dance at Chinese New Year and a cafe tradition that fed the centre for decades. What is served there is Chinese-Mexican, a cuisine of its own rather than a transplant.
The new one. Korean food in the Zona Rosa, around Hamburgo and Florencia, where a genuine Korean quarter has formed with restaurants, grocers and bakeries — the most authentic Asian eating in the city. Japanese across Polanco, the Roma and the south, from serious omakase counters to the Mexican sushi that is a genre in its own right. Plus Thai, Vietnamese and Indian in smaller numbers.
A note on sushi here. Mexican sushi means large rolls, often breaded or baked with cheese on top, with cream cheese and sauces. It is enormously popular and should be judged as what it is. If you want nigiri and sashimi, ask explicitly or go to a specialist counter.
Practical notes. The Zona Rosa Korean restaurants are walkable from Metro Insurgentes, line 1. Barrio Chino is two minutes from Bellas Artes.