餡 An or 餡子 anko, red, sweet bean paste is one of the basic ingredients for Japanese sweets. Red paste made from minced meat was originally used in China for making Manju, steamed buns. Around 600 it came from China to Japan and was used in temples, because the buddhist monks were not allowed to eat meat, red beans where used instead, also because of the pretty red color of the bean paste. Today red bean paste is a sweet, dark paste with deep taste, similar to chestnuts. It is used in Chinese, Japanese and Korean cuisine, most for confectionery. It is prepared by boiling and mashing azuki beans and then sweetening the paste with sugar. The husk of the beans may be removed by sieving before sweetening, which leads to a smoother and more homogeneous paste. Chinese red bean paste is a little different than the Japanese kind, it often contains oil or even lard. Japanese style bean paste is more refined, smoother and deeper in taste, and contains no fat and only plant ingredients.

In Japanese cuisine there are many different types of anko, strictly speaking, the term “an” can refer to almost any sweet, edible, mashed paste, although without qualifiers red beans are assumed. The most common types are made from red azuki beans, there are following types, depending on the ingredients used and / or texture:

粒餡 Tsubu-an

Tsubu-an, chunky sweet bean paste (tsubu= grain) is made from small, red azuki beans which are cooked until soft. After cooking, the paste is not pureed, there are still many whole beans. Sweet, red bean paste has a rich, deep taste and chunky texture, it is used as filling in many Japanese sweets like Daifuku Mochi, Manju, pancakes and much more.The paste is vegan and can also be used in vegan recipes insted of dairy based fillings.

Dainagon Tsubu-an has the best taste, it is made with 大納言小豆 Dainagon Azuki, a high quality azuki bean kind from Japan.

潰餡 Tsubushi-an is a partially crushed anko, there are still whole beans but also a part of azuki beans is crushed. Recipe for tsubu-an.

漉し餡 Koshi-an

Koshian is the smooth variety of sweet bean paste, the beans are cooked soft and passed through a sieve to remove all bean skins(some japanese wagashi chefs use a special horse-hair sieves, and prepare the paste by hand, it is very time consuming, but the taste is great). Smooth, red bean paste has an intense, chestnut-like taste and is used in many wagashi as filling but also as a "base" for sweets like ukishima or nerikiri.

小餡 Ogura-an is smooth bean paste mixed with whole dainagon yude azuki (a high quality kind of azuki beans that have been cooked in sweet syrup). Recipe for koshian, smooth sweet bean paste.