Soybeans (大豆 in Japanese) , known as the "meat of the field," are nutrient-rich beans that serve as an excellent source of protein. In Japan, they have been widely used as substitutes for meat and fish, especially with the spread of Buddhism, which prohibited meat consumption. Besides being eaten boiled, steamed, or cooked, soybeans are also the base ingredients for soy sauce, miso, tofu and natto (fermented soybeans). Soy-based foods are produced across Japan, supporting the country's food culture.

Soybeans are rich in protein and contain less fat compared to meat and fish. They also provide essential nutrients such as vitamin B1 (important for carbohydrate metabolism), vitamin B2 (crucial for fat metabolism), vitamin C (important for collagen synthesis), and vitamin E (helps prevent oxidation of fats in the body).

Dried soybeans can be stored for long periods at room temperature. Once boiled, soybeans should be thoroughly drained and then frozen in a plastic bag for use in various dishes. Cooked or steamed soybeans that cannot be used immediately can also be frozen similarly.

Soybeans are consumed in various forms. For example, soymilk is made from squeezed soybeans, kinako is made from roasted and powdered soybeans, ：moyashi are soybeans that have been sprouted in a dark place, and edamame are soybeans harvested before they mature.