Tempura has become an indispensable part of Japanese food. It is a popular dish that is always mentioned as one of the “Japanese food that you want to eat” and “Japanese food that was delicious” by foreign tourists who are increasing year by year. However, tempura is not an ancient Japanese dish, but a Nanban dish that was introduced from Portugal to Nagasaki with the introduction of guns about 400 years ago (in the middle of the 16th century). In Japan at that time, oil was very valuable for lighting, so tempura, which uses a large amount of oil for cooking, was treated as a luxury dish. With the increase…