Masako Aoki, a Japanese sinologist translated by Mr. Zhou Zuoren, wrote in "Bai Mei, a Pickled Recipe in China": "It seems that there is no dried prune with perilla in China. There is a pickled Bai Mei without perilla, which has existed since ancient times and is also used in vegetables. This method also spread to China. When making plum sauce, perilla is added, which has been the case since ancient times. " Regarding Bai Mei, Mr. Zuo Ren commented: "It refers to Japanese pickled sour plum, which is the most common and common daily dish. Ordinary people's lunch boxes are prunes except rice. " Directly using salted prunes as side dishes, of course, is to increase appetite first. In the past, the diet structure of Japanese people was mainly cereals and vegetables with high fiber content, which was simpler than ours. In fact, plant fiber has not been digested, and it expands into a larger volume after absorbing water in the stomach, which makes people feel full. For civilians who work all day, this is obviously not conducive to the heat needed by the body. Plums are rich in organic acids, which can stimulate the secretion of gastric juice and stimulate appetite, so we should grasp this point. So, Japanese food.