Umeboshi is a traditional Japanese pickle made from plums. The ingredients for making umeboshi include plums, salt, and red shiso leaves. To make umeboshi, start by washing the plums and removing any stems. Then, place the plums in a container and sprinkle them with salt. Let the plums sit for a few hours to draw out the excess moisture. After that, rinse the plums and place them back in the container. Add red shiso leaves for flavor and color. Finally, cover the container and let it ferment for several weeks. Umeboshi is known for its tangy and salty taste, and it is often enjoyed as a condiment or used in various Japanese dishes.