Japan (anko documented from Nara period; Buddhist prohibition on meat accelerated development of sweet bean preparations as celebratory and ritual food; azuki beans cultivated in Japan for over 2,000 years)
Anko (あんこ, sweet bean paste) is the foundational preparation of Japanese wagashi — made from azuki beans (Vigna angularis) cooked down with sugar to a paste of varying consistency. The two primary forms are tsubu-an (粒あん, textured paste with whole beans partially intact) and koshi-an (こしあん, smooth, fine paste with all skins removed by straining). The quality of anko depends entirely on the azuki bean variety and origin (Hokkaido's Tokachi region is the premium source), the ratios of sugar to bean, the cooking time, and the degree of final water removal (the anko must be 'fried' in the pan to the correct moisture level). Premium anko from master wagashi confectioners uses a 1:0.8 ratio of cooked bean to sugar — slightly less sweet than commercial versions — and maintains the distinctive earthy-sweet balance that defines high Japanese confectionery. Shiroan (白あん, white bean paste from navy or white kidney beans) is the second major paste, subtler in flavour and used for more delicate wagashi where the filling should not compete with the wrapper.
Earthy, naturally sweet, with the distinctive azuki bean nutty-legume character. Tsubu-an — textured with bean skins, more rustic and flavour-pronounced. Koshi-an — silky smooth, refined, slightly more subtle. The characteristic anko flavour is unique: neither fully sweet nor savoury, with the bean's tannin providing crucial bitter balance to the sugar.
{"Azuki beans must be pre-cooked in at least two changes of water — the first water extracts bitter tannins that would dominate the finished anko","The sugar is added in stages to the cooked beans, not all at once — gradual sugar addition allows controlled moisture reduction and prevents the beans from toughening","The 'frying' stage (karameru) in the final minutes over medium heat removes excess moisture to the correct paste consistency","Koshi-an straining requires the hot bean mixture pressed through a fine sieve — the skins are discarded and only the smooth flesh passes through","The finished anko should be glossy, cohesive, and hold its shape without being dry or crumbly"}
{"Tokachi azuki from Hokkaido is the unambiguous premium choice — smaller bean, more intense flavour, the benchmark for professional wagashi makers","The moisture content of finished anko can be tested by taking a small amount between fingers — it should hold its shape but not stick to dry fingers","Adding a pinch of salt to the anko in the final minutes brings forward the bean's natural sweetness and adds complexity","For nerikiri (fine wagashi made from shiroan and sweet potato base), the shiroan must be significantly drier than regular anko to allow moulding","Pair anko wagashi with matcha (koicha or usucha) — the bitter-earthy matcha and sweet-bean anko is one of Japan's foundational flavour dualities"}
{"Single-water cooking of azuki — the tannins in the first cooking water create a harsh, bitter note that persists through the anko","Adding all sugar at once at the start — prevents full bean cooking, creates a grainy texture, and produces a more one-dimensional sweetness","Under-'frying' the final paste — insufficient moisture removal creates a runny anko that makes daifuku mochi sticky and impossible to shape","Over-cooking the beans to mush — tsubu-an specifically requires beans that are cooked through but retain some structural integrity","Using granulated white sugar exclusively — traditional anko uses a small proportion of light brown sugar or wasanbon for depth; all-white sugar creates flat sweetness"}
Tsuji, Shizuo. Japanese Cooking: A Simple Art