A pickled plum, often known as umeboshi, is a traditional Japanese food made from ume fruit, which is a type of sour plum. The plums are typically salted and then fermented, resulting in a tangy, salty flavor. They are usually bright red or dark brown in color and are often used as a condiment or side dish in Japanese cuisine. Pickled plums are not only flavorful but also have various health benefits. They are rich in antioxidants and are believed to aid digestion and boost the immune system. In Japan, they are commonly served with rice or used in onigiri, a popular rice ball dish.