Tofu is definitely one of the major processed foods eaten in Japan. Originally from China, tofu is eaten throughout the year in Japan.
Most common ways to eat tofu are Mapo tofu, hot pot, miso soup, chanpuru and hiyayakko. Hot pot which is tofu as the main ingredients is called Yudofu which means Hot water tofu. Putting tofu into hot pot or miso soup is very common and popular ways to eat tofu but actually tofu does not have to be included into the hot pot or the miso soup. There are hot pot and miso soup without tofu.
Hiyayakko, which is a popular dish at izakaya tavern or diner. Hiyayakko is cold tofu which is not cooked at all. Just seasonings are toppings are added on the tofu with soy sauce. Usually chopped scallions, grated ginger and dried bonito flakes.
Hiyayakko is mostly eaten in summer and accompanied with beer. However, it is provided at restaurants not as seasonal menu, therefore you can try it anytime.