It would be difficult to imagine Japanese cuisine without tofu. In Japan until the mid-1800s, eating meat was officially banned on religious grounds. Tofu is a rich source of protein and was readily available, so it became part of the daily diet. Even today, it would be hard to find a town anywhere in the country that does not have a tofu maker.

The main ingredient in tofu is soybeans. Dried beans are soaked in water for a few hours and then mashed. Water is added to the mash, which is then filtered to make a milky substance that will become soymilk. The liquid is simmered, and then a hardening agent such as nigari (magnesium chloride) or sekko (calcium sulfate) is added to make the "milk" coagulate into tofu. About 90% of tofu is water, so the taste depends greatly on the quality of the water and the beans.

Kyoto, the old capital of Japan, has many underground springs, and the city has long been known for the excellent quality of its water. Shops specializing in tofu first appeared there around the 17th century, and before long, working class people were eating it on a regular basis. Prior to that, it was made mainly at Buddhist temples. Because Kyoto had many temples and fine water, tofu became one of the city's best-known products. A reference book on cooking and medicinal herbs called Honcho Shokkan (published in 1697), praised the subtle taste: "Tofu made in Kyoto is delicate, soft, and as white as snow."

Tofu is an excellent source of vegetable protein and has a light flavor that is ideal for a wide variety of dishes. It is often eaten diced in miso soup or straight from a pot of simmering broth. To really appreciate the delicate flavor of tofu, it is best to choose a simple recipe. In the summer, one good choice is hiya yakko—chilled tofu served with a spicy topping of grated ginger or chopped green onions, sprinkled with soy sauce. But when it is cold outside, nothing could be better than yudofu.

To prepare yudofu, simmer kombu seaweed in plenty of water in a large pot. Cut fairly soft tofu into good-sized blocks and then add to the pot. When eating, dip the tofu in a sauce or broth containing soy sauce. Yudofu, so simple to make, is often eaten in Japanese homes, and Kyoto has many restaurants specializing in it.

The Sagano district in northwestern Kyoto is said to have some of the best water in the city, and large quantities of tofu have been produced there for centuries. One shop, called Morika, has made tofu since the 1860s. It stands near the Saga Shakado Hall (Seiryo-ji Temple).

If you are in Kyoto, you can try out the shop's tofu at a yudofu restaurant called Seizansodo, where the yudofu for these photos was prepared. The restaurant is located on the grounds of Myochi-in, a Buddhist chapel in Tenryu-ji Temple. Sitting in a tatami mat room facing the garden, eating a tofu meal with a cool breeze blowing through, is an enjoyable experience you will never forget.

Tofu is a ready-to-eat food needing little preparation, so if you make yudofu, be careful not to simmer the tofu for too long—you could scald your tongue and the tofu would lose some of its flavor. It tastes best when eaten as soon as it is nicely warmed right to the middle.