Tofu is made from soybeans, water, and bittern and "Sumashi (clarifying)" powder, both of which are coagulants. Soybean protein has a well-balanced composition of essential amino acids and is high in nutritional value. Unlike animal protein, which can be a cause of the accumulation of cholesterol, soybean protein works to reduce cholesterol levels and thus is highly regarded as a health-enhancing food. Lately, tofu has been drawing attention as a diet food as it is rich in both vitamins and minerals and low in calories. In addition, tofu appears to have ingredients that may help retard the aging process as priests on a vegetarian diet and those living in regions with higher tofu consumption levels tend to live longer.

In Japan, approximately 850 soybean varieties are planted. Among them, varieties that have relatively higher protein contents and sweeter taste are used to make tofu. Tofu varieties differ from one region to another.

Mr. Morii, the head of a long-established, family-run tofu shop in Kyoto, says that the quality of soybeans is very much dependent on the weather and soil composition in the particular year in which they are grown and that the actual quality remains unknown until they have been processed into tofu. It is thus extremely difficult to select the right soybeans.

Mr. Ishii, owner of 360-year old tofu shop "Okutan" in Kyoto and a Yudofu (Boiled tofu) restaurant run by his family says "The quality of tofu is very much dependent on the soybeans." For a quarter of a century he has been studying pulses from all over the world. Recently, he began cultivating chemical-free soybeans himself to produce "Mukashi tofu" (traditional-style tofu) using time-honored techniques.

The annual consumption of soybeans in Japan exceeds 5 million tons, of which only 4% are cultivated domestically. The soybeans being cultivated in Japan for commercial distribution or any other purposes are not genetically modified.