Short answers, pulled from the story.
Traditional Japanese cuisine is called washoku. It is based on rice served with miso soup and side dishes, with an emphasis on seasonal ingredients. Side dishes often include fish, pickled vegetables, tamagoyaki, and vegetables cooked in broth.
Japan banned eating meat because of adherence to Buddhism, which became the official religion at the end of the Kofun period and the beginning of the Asuka period. In 675 AD, Emperor Tenmu prohibited eating horses, dogs, monkeys, and chickens, and later emperors widened the ban to nearly all mammals except whale, which was categorized as a fish.
Emperor Meiji lifted the ban on red meat in 1872 as part of the Meiji Restoration and the opening of Japan to Western influence. That year a New Year's feast featured European dishes, and for the first time in a thousand years ordinary people were allowed to eat meat in public.
Sushi originated as a means of preserving fish by fermenting it in boiled rice, where lactic acid fermentation prevented the bacteria that cause putrefaction. During the 15th century, advances shortened the fermentation to about one to two weeks, and the hand-rolled and nigiri types were invented in the 19th century.
Washoku was added to UNESCO's Intangible Cultural Heritage list on the 4th of December 2013, recognized notably for the celebration of New Year. The listing brought the number of Japanese assets on the list to twenty-two.
Japanese cuisine spread globally largely through sushi and ramen, with the California roll created in North America in the 1970s helping drive sushi's worldwide popularity. Dishes are often adapted to local palates, such as sushi Mexicano with chiles in Mexico and halal-adapted Japanese food in Indonesia.