Konnyaku is a gelatinous food made from Konnyaku potatoes. It is usually sold in a block, but also in a pasta or thread like shape (Ito Konnyaku, also called Shirataki).
Konnyaku is often used in Nimono (boiled and seasoned vegetables). Konnyaku doesn’t have very much taste itself but absorbs flavors from seasonings. It also provides a nice texture, a little chewy or springy. It has a distinct smell, and you can boil it to lessen the smell before used in cooking.
Konnyaku is rich in fiber and low in calories. With little calories or fat, Konnyaku can be used as a substitute for starches when preparing low calorie dishes.