Heshiko: Fukui's Fermented Delicacy

Preserved Seafood and the Mackerel Road

Heshiko emerged during the mid-Edo period, long before the advent of refrigeration and efficient transportation. Preserving food was vital, particularly during the harsh winters in regions along the Sea of Japan. Heavy snowfall, freezing temperatures, and turbulent seas often prevented fishermen from taking their boats out to catch fresh seafood.

Wakasa Bay has historically been an important source of seafood, including Fukui amaebi (sweet shrimp), Echizen crab, horsehead tilefish, and mackerel. Mackerel, in particular, is highly perishable, and prompted fishermen to develop innovative preservation methods. These included grilling the fish on the beach immediately after landing it and using salting and pickling techniques. Along the Echizen coast, one such method involved gutting the fish, salting it, and pickling it in rice bran—which is more or less how heshiko is made today.

In ancient times, preserved seafood from Wakasa Bay, including salted mackerel, was transported to the imperial courts in Nara and later Kyoto. These goods were transported along a network of routes known as the Mackerel Road (Saba Kaido). Visitors can still walk sections of the Mackerel Road and visit towns that developed along it.

How Heshiko Is Prepared

While mackerel is the most common fish for heshiko, some varieties use sardines, squid, and fugu (puffer fish). Preparation methods vary by region and household, though making heshiko at home has become less common.

To prepare heshiko, fresh fish are scaled, gutted, and then heavily salted. Afterward, they are layered and tightly packed in a barrel or tub. Weights are placed on the top layer to compress the fish and remove excess water. After about a week, the fish are cleaned, stuffed and coated with rice bran, then returned to the container and compressed again. They are left to ferment for about six months; in some regions, fermentation is extended up to a year to enhance the flavor. Additional seasonings such as mirin, soy sauce, chili powder, or fresh chilies, can be added for different taste variations.

During fermentation, bacteria and yeast present in the rice bran and fish break down the proteins, fats, and carbohydrates. This creates heshiko’s unique flavor, texture, and nutritional qualities. Lactic acid bacteria help to preserve the fish by preventing the development of harmful bacteria and spoilage organisms.

Heshiko is considered good for health, with many nutritional benefits. Mackerel, for example, contains peptides known to support immunity, aid recovery from fatigue, lower blood pressure, and improve circulation. The fermentation process amplifies these benefits, with lactic acid bacteria contributing to immune regulation and gastrointestinal health.

How to Enjoy Heshiko

Heshiko is known for its firm texture, intensely savory flavor, and distinctive aroma. It is often first brushed to remove excess rice bran, then sliced and lightly grilled. The amount of rice bran left on the fish before grilling is a matter of personal taste, though leaving too much may cause it to burn. Heshiko can also be served without grilling, as sashimi. Its bold flavor pairs particularly well with local sake, such as the “junmai (pure rice sake)” varieties like Hakuryu from Yoshida Breweries.

Another traditional application of heshiko is in narezushi, considered a precursor to modern sushi. To make narezushi, heshiko is taken out of the fermentation tub, rinsed, and soaked in water for a day to draw out excess salt. The skin is removed, and the rice bran in the stomach cavity is replaced with steamed rice and koji (steamed rice mold). The fish is then returned to the tub, which is packed with more koji, and left to ferment for another 10 to 20 days. Once ready, it is sliced and served. Narezushi is often enjoyed on special occasions in Fukui, such as New Year's, and can be stored for up to 10 days, depending on the temperature.

Mihama, known as the “Town of Heshiko,” has several heshiko storehouses in the Hiruga district near the harbor. Learn about the techniques of preserving fish from local experts, who guide visitors through the steps while sharing their stories and insights about the local food culture. After seeing the fermenting process, there are options to sample heshiko sashimi. Heshiko Chaya, a small restaurant above a heshiko storehouse, serves a variety of dishes, such as heshiko tempura and sashimi and affords views of Wakasa Bay.