To make shio-katsuo, frozen bonito is defrosted, cleaned, and salted inside and out with a large quantity of salt over two weeks. It is then dipped in salt-dip that has been used for previous preserving, before being rinsed with clean water. The bellies of the fish are opened with bamboo skewers, and two fish are tied together and hung in pairs. The fish then dry in a shady area for about three weeks.
Shio-katsuo can be eaten sliced thinly and marinated in vinegar or lemon, and pairs well with sake. Another traditional dish using this product is ochazuke, which consists of a bowl of rice and a bit of the fish topped with hot water or tea, creating a soup dish with a strong umami flavor. Shio-katsuo flakes can also be used as a seasoning or topping for udon noodles, pasta or salad.
People began producing shio-katsuo regularly during the Edo period (1603 – 1868) in the district of Nishi-izu. It is not only thought of as a food, but also as a sacred food offering to God. Dried bonito was also used as a currency in paying taxes. Shio-katsuo was also part of the New Year’s celebration, where it would displayed in front of houses or in shrines in the hopes of a good fishing season and protection at sea and luck and prosperity for individual families. The product was also part of a traditional feast shared among fishermen at the end of the season; sharing this dish together meant the same crew would work together at the next season. While shio-katsuo is still part of New Year’s festivities, the custom of the shared meal related to the fishing crew has been lost.
Today, just a handful of producers still make shio-katsuo, processing about 800 bonitos per year. The product is mainly consumed locally, both for special occasions and as an every day food. The use of the fish in the traditional New Year’s celebration, though, is declining, and with most producers in their 60s with no young people to continue the tradition, shio-katsuo is on the brink of being lost for good.