Later yesterday, I visited the supermarket and decided to have a look at the prepacked bases. There were about 20 different brands, none of which are based in Sichuan or Chongqing. The people there don't need them!
This one, from way up north in Hebei province beside Beijing, seems to be the most popular. The main ingredient is beef tallow at a huge 28.7%. They also contain a load of preservatives etc. They do describe it as for Sichuan style hot pot.
Here is a short video of a factory making the stuff. It is in Chinese, but the beef fat is the first ingredient you see . If that doesn't put you off, little ever will!
