Umeboshi is a product obtained by the processing of the Japanese plum (Prunus mume), which is dried and then salted. The recipe for shikinbai was left directly by Nariaki Tokugawa, the ninth ruler/lord of Mito, who had a great number of plum plants planted in the Kairakuen garden, considered one of the most beautiful gardens in Japan. There were mainly two reasons for the high quantity of this fruit: the plum flowers announced the beginning of the spring, giving hope for the future. On the other hand, it was the best food for the military, because it helped quench the thirst. Damaged or imperfect plums were pounded with a hammer to remove the seeds, and only the flesh was placed in brine with red shiso (a herbaceous plant used as a culinary herb), which imparts the characteristic reddish color. This product does not contain chemical seasonings, only salt and red shiso.
Umeboshi is a low-calorie food, almost without fat, and rich in fibers, mineral salts, carbohydrates, and B and A1 vitamins. Its consumption has beneficial and detoxing effects on the liver, improves symptoms of gastro-esophageal reflux, has antibacterial properties, and prevents the occurrence of tooth decay. It is also a useful product in cases of anemia, to counter nausea and fatigue, and more generally for the proper functioning of the body.