Japanese Tofu is a soy product that is used in many Japanese dishes, like Miso Soup and Nabemono (hot pot) dishes. Soy milk is solidified by mixing it with a coagulating agent, Nigari bitterns derived from sea water, to make Tofu. This white soft curd doesn’t have much taste itself other than a mild soy flavor, but it absorbs seasonings well during cooking. You can also eat Tofu without cooking, such as Hiyayakko.
The most commonly used types of Tofu are Kinugoshi, sometimes called silken, which is very soft and smooth, and Momen, which is more firm and dense. You can use either one, but use Kinugoshi when you like to enjoy a softer and more delicate feeling in your mouth. Kinugoshi can break apart easily though, so if you use Tofu in a dish and you don’t want to crush it into a million little pieces, using firmer Momen may be better. There are other types as well, such as Yakidofu (Tofu where the surface is grilled; often used in Sukiyaki), and Atsuage (thick) and Usuage (thin) deep-fried Tofu.
In the US, Tofu is usually sold as a block submerged in water in the refrigerated section of most grocery stores. You can also find vacuum packed Tofu, which is great for keeping in your pantry because of the longer shelf life at room temperature.