Anko is a sweet red bean paste commonly used in Japanese cuisine. It is made from azuki beans, which are boiled and sweetened with sugar. Anko can vary in texture, being either smooth or chunky, and is often used as a filling in various desserts, such as mochi, dorayaki, and taiyaki. There are different types of anko, including koshian, which is a smooth version, and tsubuan, which retains some of the bean's texture. Anko is not only popular in Japan but also in other East Asian countries, where it is used in a variety of traditional sweets.