Fondue of old time

I remember when I was in VN, we often used this type of fondue, where the hole in the middle was filled with hot charcoals to warm the soup. There is no electricity or gas, only charcoals.

Now there are plenty of more "convenient", and clean fondue, easy to clean, but I was quite happy to find a VN restaurant here last week that is still using this ;-). Brought nostalgy.