What Is Anko? A Guide to Japan's Sweet Red Bean Paste
If wagashi has one defining ingredient, it’s anko. It fills daifuku, sits between dorayaki’s two pancakes, fills manju, forms the entire body of yokan, and gets wrapped in an oak leaf as kashiwamochi. But the sweet, familiar paste most people picture today isn’t how anko started out.
Anko didn’t start out sweet
Anko arrived in Japan from China during the Kamakura period (1185 to 1333), originally as a filling for buns, made with meat and vegetables in its Chinese form. Zen monks who traveled to China and brought the tradition back substituted azuki beans for the meat, in keeping with Buddhist dietary practice, and salted the result rather than sweetening it. This savory bean filling became part of a monastic breakfast tradition that later fed into the development of manju and yokan as distinct sweets.
How anko is actually made
Anko starts with dried azuki beans, soaked and then simmered. Before any sweetening happens, most anko goes through shibukiri (渋切り), a bitterness-removal step: the beans are boiled, the water is discarded once it turns a deep reddish color, and fresh water is added to boil again. This gets repeated anywhere from once to about four times. More repetitions produce a cleaner, less bitter flavor, but also strip away some of the beans’ natural color and taste, so makers balance the two rather than simply maximizing repetitions.
Once the beans are fully softened and the bitterness is managed, sugar is added and the mixture is cooked down to the desired consistency. Traditional anko recipes lean close to a 1:1 ratio of sugar to beans by weight, though individual makers vary that ratio anywhere from around 70% to over 120% depending on how sweet they want the result and how long it needs to keep; a fuller sugar load isn’t just about taste, since sugar also helps preserve the finished paste longer. From there, the beans are either strained smooth or left with their skins intact, the choice that separates koshian from tsubuan. Our guide to koshian vs tsubuan covers that split in full, along with a third named style, ogura-an, and shiro-an, the same production logic applied to white beans instead of azuki.
A specific, well-documented example: how manju got its filling
The general Kamakura-period Zen-monk story explains the pattern; one specific, well-documented later case shows it in action. In 1349, a Chinese man named Lin Jingyin, known in Japan as Rin Jōin, arrived in Nara accompanying the Zen monk Musō Soseki and brought with him the recipe for mantou, the Chinese steamed bun. Since his Buddhist practice ruled out a meat filling, he substituted sweetened azuki paste, opened a shop, and sold the result as manju. It caught on quickly, reportedly reaching the imperial court itself, and Nara’s Kango Shrine (also known as Rin Shrine) still holds an annual manju festival in his honor, where confectioners from across Japan bring their own sweets as an offering.
Why red beans specifically
Azuki’s red color carries real cultural weight in Japan, traditionally associated with good fortune and warding off misfortune. That symbolism shows up most directly in sekihan, a savory sticky rice dish studded with azuki beans and dyed reddish by their color, served on celebratory occasions like births, weddings, and New Year. Azuki’s use in wagashi and its use in celebratory sekihan both draw on the same underlying association between the bean’s color and good fortune, even though one is sweet and the other isn’t.
Frequently asked questions
What is anko made from?
Azuki beans, cooked, sweetened (usually with sugar), and either strained smooth (koshian) or left chunky with the skins intact (tsubuan).
Was anko always sweet?
No. Anko arrived in Japan from China during the Kamakura period as a savory, salted filling, brought back by Zen monks who substituted azuki beans for meat in Chinese-style buns. Sweetened anko only became the standard during the Edo period, once domestic sugar production expanded.
What is shibukiri?
A bitterness-removal step in making anko: the beans are boiled, the water is discarded, and fresh water is added to boil again, repeated up to about four times. It's done before sweetening, and removes bitterness from the bean skins at some cost to the beans' natural color and flavor.
What's the difference between koshian and tsubuan?
Whether the bean skins are strained out. Koshian is pushed through a fine mesh or cloth for a smooth paste; tsubuan keeps the beans whole or lightly mashed for a chunkier texture. Our dedicated guide to koshian vs tsubuan covers the full comparison, including a third named style, ogura-an.
Who is credited with inventing manju?
Lin Jingyin (known in Japan as Rin Jōin), a Chinese man who arrived in Nara in 1349 with the Zen monk Musō Soseki, bringing the recipe for a Chinese steamed bun and substituting sweetened azuki paste for its meat filling since his Buddhist practice ruled out meat. Nara's Kango Shrine still holds an annual manju festival in his honor.
Why are red beans specifically used in Japanese celebrations?
Red has traditionally been associated in Japan with good fortune and warding off misfortune. That's why azuki beans, with their reddish color, also appear in sekihan, a savory celebratory rice dish served at births, weddings, and New Year, alongside their much more common use in sweet wagashi.
The short version
Anko is sweetened azuki bean paste, wagashi’s single most common ingredient, but it started out as a savory, salted filling brought from China by Zen monks during the Kamakura period, and only became sweet once sugar became widely affordable in the Edo period. One well-documented later case shows the pattern directly: Lin Jingyin’s 1349 invention of manju in Nara, still honored with an annual festival today. Making anko starts with shibukiri, a bitterness-removal technique of repeatedly boiling and discarding water, before sweetening (traditionally close to equal parts sugar and beans by weight) and cooking the beans down into either a smooth or chunky finished paste. Azuki’s red color also carries its own cultural weight in Japan, tied to good fortune well beyond its role as a dessert ingredient.