Heshiko Salted Bluefish Aged in Rice Bran from Wakasa

What Heshiko is

Heshiko (へしこ) is a regional preserved seafood made by salting bluefish and then maturing it in rice bran (nukazuke). It is a traditional food of the Wakasa area of Fukui Prefecture, the Tango Peninsula in Kyoto Prefecture, and parts of Ishikawa Prefecture. Historically it served as an overwintering preserved food. In December 2007 “saba no heshiko” (mackerel heshiko) was chosen as one of the Agricultural, Mountain and Fisheries Villages’ Hundred Local Dishes.

Names and origin theories

Several folk etymologies appear in local accounts. One long-standing explanation ties the name to the fishermen’s verb heshikomu — to press or cram fish into a barrel — yielding the idea of “what has been pressed.” Another theory derives the word from an old term for the liquid that seeps from the fish during salting. A third proposal, recorded in an Ainu dictionary by Shigeru Kayano, links heshiko to an Ainu term (pe-si-kor) meaning roughly that seeping liquid produces the taste and preservation qualities.

How it is made: traditional steps and modern additions

The basic technique is simple in outline but variable in detail between households and producers. Fresh bluefish — mackerel is the representative fish — are cleaned, salted on both sides and first left to draw out liquid. The juice that comes out during that initial salting is an important ingredient for the later marinade (local accounts call it “shie”). After the initial salt stage the fish are placed into a rice-bran mixture with salt for the main maturation.

Modern makers commonly add flavoring to the rice-bran or to the marinade: fish sauce, soy sauce, mirin, shochu or sake lees are all used by different producers. Those additions, and differences in the local climate, make the final flavours subtly different from one maker to another.

A documented home-style method from a Mihama inn illustrates the detailed sequence used by a single producer: the mackerel are split along the back, washed with a sasara to remove blood and internal residues, and then hand-salted until the flesh appears completely white. The fish are reassembled, packed tightly in a tub and pressed under weight for about 10 days to two weeks until the brine (shie) appears. That shie is used to wash off any remaining loose salt; it is then boiled, the scum skimmed and the liquid strained to a dark, soy-sauce–like base. Soy sauce, sake and mirin are added to make a house marinade. The fish are dipped in that marinade, arranged skin-down with flesh-up, layered in the tub and covered with rice bran; they are pressed again under weight and left to mature — in this example for around ten months. Some households alter the weight during maturation or add extra marinade as the bran soaks up liquid.

Taste, uses and culinary relatives

Heshiko is characteristically salty but intensely savoury: the preservation concentrates umami. Lightly brushed of rice bran and briefly grilled, it is used as a rice accompaniment, for ochazuke or as a sake snack. When the product is very fresh it can be served raw as sashimi after removing belly bones and the thin outer skin. Because of its concentrated savour, producers and cooks in Wakasa have experimented with Western-style uses: heshiko appears in local recipes for spaghetti, carpaccio, sandwiches and quiche.

A related family of rice-bran–fermented fish exists in Hokkaido — examples include nukanishin (herring) and nukasanma (saury). Local histories record that the method of rice-bran preservation spread northward along the routes of the Kitamaebune trading vessels.

Mihama: preservation, promotion and community activity

Mihama Town in the Wakasa area features prominently in the modern story of heshiko. Faced with a decline in beach visitors, the town began discussing local foods suitable for regional revitalisation in 1997 and focused on saba heshiko as a signature product. Mihama pressed its identity around heshiko: the town applied in 2004 and in May 2005 registered the trademark “Heshiko no Machi”; in 2006 a promotional mascot was created to support PR activities.

Research attention arrived in 2003 when a professor at Fukui Prefectural University reported that heshiko contained about 2.5 times the amino acids and about five times the blood-pressure–suppressing peptides compared with raw mackerel, prompting interest in heshiko as a health-related food. That same year, Mihama’s heshiko sold briskly at the Wakasa Road Expo 2003, raising the profile of the town’s product.

Production in and around Mihama expanded in the 2000s: in 2003 six producers made about 146,500 pieces; by 2006 eight producers made about 214,000 pieces, representing roughly 41.2% of Fukui Prefecture’s heshiko output at that time. Local producers and town government continued to coordinate: in 2015 all heshiko producers in Mihama formed the Mihama Heshiko Union (13 companies and individuals), and in June 2019 “Mihama no Heshiko” was registered as a regional collective trademark. Community groups and ryokan proprietors have also won awards for their heshiko products, and the dish appears in school lunches and in student PR activities.

Preparing and eating heshiko at home

Before cooking, take the fish from its container and spread it open. Remove the rice bran with your hands and keep that bran — it is full of flavour. Fillet the back-opened fish into two pieces and cut into bite-sized portions of roughly 3 centimetres. If you cannot eat a portion at once, wrap single pieces in plastic wrap and freeze them in a zipper bag.

The used rice bran makes a simple furikake if you toast it gently with sesame on low heat. Leftover bones make a rich stock. When grilling, be cautious: rice bran burns easily, so lower heat and slow, even cooking are recommended. To eat the fish raw, remove the belly bones, turn the fillet over and peel away the thin skin before slicing into serving pieces.

FAQ

What fish are used for heshiko?

Mackerel is the representative fish, though sardine and blowfish are also used.

Where is heshiko traditionally made?

It is a traditional dish of Fukui’s Wakasa region, Kyoto’s Tango Peninsula and parts of Ishikawa Prefecture.

How long is heshiko matured in traditional recipes?

In a cited Mihama household method the fish are pressed initially for 10 days to two weeks and then matured under rice bran for about ten months.

Can heshiko be eaten raw?

If it is very fresh heshiko can be served as sashimi after removing belly bones and the thin outer skin.