Thick, slippery udon noodles in a simple dashi-based soup are the very definition of comfort food when the weather turns cold.
Two of the most popular everyday hot udon soups are named after animals that have a special place in Japanese folklore and the Shinto religion: the kitsune (fox) and the tanuki (Japanese raccoon dog). Kitsune udon is udon soup topped with a plump square of abura-age (deep-fried flat tofu) that's been simmered in a salty-sweet broth. Tanuki udon uses the same soup, but is instead topped with tenkasu (also called agedama; tempura batter crumbs), which add flavor and richness to the soup at little cost.
Both kitsune and tanuki udon soups probably debuted sometime in the late Edo Period (1603-1868), although there are conflicting theories that suggest the soups may have been invented later.