The word originated from the Southern Song Dynasty proverb "bento", which means "convenient things, convenient and smooth". After it was introduced into Japan, it was marked with words such as "access road", "distinguishing road" and "distinguishing when" [1]. The word "bento" was later introduced back to China because it originated from the Japanese word "dang" (new font: dang, old font: bian dang), that is, the bento used to be called in Chinese mainland or the lunch box called in Hong Kong; In early Taiwan Province, it was called rice bag in Minnan dialect, but it was often called bento because of the influence of Japanese occupation. But in Chinese mainland, Hong Kong and Macao, "bento" refers to Japanese bento. Lunch boxes are usually used for lunch and dinner, not at home, and not eating in restaurants, that is, take-away, picnics, etc., in order to save time and save work such as cooking and washing dishes. You can buy a ready-made lunch in the store, or call a takeaway shop, or go to a buffet shop and choose your favorite side dishes. Bento is also one of the ready-to-eat goods sold in convenience stores. In Taiwan Province, before nutritious lunches were popularized in schools at all levels, many students took home-made lunches to school. Usually put it in the "steaming room" in the morning, and then fetch the steamed lunch at noon.