Let’s review! As long as you see the word, “donburi,” that’s rice bowl, isn’t it? Now what does “tanin” mean? “Tanin” means “strangers.” In this case, the very strangers to each other are “beef (or some other kinds of meat)” and “eggs.” They are NOT related to each other, are they? That’s why it is called “Tanin Donburi.”
Similar sauce used in “Oyako Donburi” is used when cooking “Tanin Donburi.” Just ingredients are different – They are strangers! Then, why do you cook “strangers” together? Kind of weird… See – in Japanese Kado (the art of flower arrangement) you are not supposed to mix up the flowers from water with those from land in one particular arrangement. They are arranged differently. Same thing with this “Tanin Donburi.” They don’t quite match in one bowl together. That is why “Tanin Donburi” is NOT so popular as “Oyako Donburi” in Japan.
(This is how “Tanin Donburi” is cooked.)