Japan — particularly Kyushu, Shikoku, and the Inland Sea coast where small oily fish (katakuchi iwashi, urume iwashi) were abundant
Iriko dashi (also called niboshi dashi in eastern Japan) is made from small dried anchovies or sardines and is the most assertive, mineral-forward of the four primary Japanese stocks. Used heavily in miso soup in Kyushu and western Japan, as a base for udon in certain regional styles, and in strongly flavoured simmered dishes that can stand up to its bold character. Unlike the clean, delicate profiles of kombu dashi and katsuobushi dashi, iriko produces a deeply savoury, slightly bitter, distinctly oceanic stock that makes food taste unmistakably of the sea. The bitterness is a feature — it creates depth and complexity — but requires management through technique.
Bold, mineral, assertively fishy with controlled bitterness, deep oceanic character, high glutamate and inosinate content
Remove the heads and pinch out the dark digestive tract (the black line running through the belly) before use — these are the primary sources of harsh bitterness. Cold-start method preferred: place cleaned iriko in cold water, bring to 60°C slowly, hold 20 minutes, then strain — this extracts sweetness before bitterness compounds are liberated. Quick-method: steep in room-temperature water overnight and strain without heating. Ratio: approximately 20–30g iriko per litre of water. Iriko pairs exceptionally well with kombu — combining produces a synergistic umami amplification similar to awase dashi.
Toast iriko briefly in a dry pan before simmering to develop nuttier, sweeter notes — this is traditional in some Kyushu preparations. The spent iriko after dashi-making can be simmered in soy sauce, mirin, and sugar to make a nutritious tsukudani-style topping for rice. Mix iriko dashi with kombu dashi in a 60/40 ratio for an excellent all-purpose udon broth base.
Skipping head/gut removal, producing medicinal bitterness. Boiling aggressively — high heat liberates harsh bitter alkaloids from the dried fish. Using iriko past its freshness window; stale dried fish produce rancid rather than clean fishy notes. Treating iriko dashi as interchangeable with katsuobushi dashi — its stronger character requires adjustments to miso quantity, seasoning balance, and companion ingredients.
Tsuji, Shizuo — Japanese Cooking: A Simple Art; NHK World — Dashi documentary series