While Tanindon can technically be made with any meat other than chicken, there are a few things to keep in mind. Because the meat is simmered for only a short amount of time in liquid, it can become tough and dry. To get around this, you want to use a well-marbled cut of meat that is sliced very thinly. Japanese supermarkets usually have meat for Sukiyaki (or shabu shabu) that's marbled and sliced thinly. If you don't have one near you, you can slice your own beef by chilling it in the freezer until it's firm (but not frozen), and then use a very sharp knife to cut thin slices against the grain. Thinly sliced pork belly is another good option for making Tanindon.