The Origins of Sushi

The original type sushi was called narezushi (fermented sushi) and has a history stretching back over a thousand years. Japan has a long history of fermented foods, which includes familiar ingredients such as soy sauce, miso, and natto fermented soybeans. Similarly, narezushi originated as a preserved food in a time before refrigerators, made by fermenting fish, salt, and rice with lactic acid.

Historical documents have revealed that during the Nara Period (710–794 CE), when Obama, a city in Fukui Prefecture that was part of the ancient Wakasa Province, was known as a miketsukuni (a province that supplied food to emperor), the fish that were caught there were transported in the form of sushi to the capital in Heijo-kyo (the ancient name for Nara). But what kind of food is narezushi, the precursor to modern sushi? We spoke to Sasuke Morishita, who continues the tradition of mackerel narezushi in Tagarasu District, a fishing village located in eastern Obama.

Carrying on the culinary traditions of heshiko and narezushi

The beautiful sea of Wakasa stretches out in front of the old-fashioned townscape. Sometimes you can see ships come and go through the waves. “It’s a nice view, isn’t it?” says Morishita with a smile.

“One of the distinguishing features of narezushi made in Tagarasu District is that we start the pickling process with mackerel heshiko. Heshiko means fish fermented in rice-bran paste. We pickle the fatty mackerel in brine and rice bran (a powder of rice hull and germ made when milling brown rice into white rice), a process which takes a whole year. Then we take mackerel heshiko and ferment it in plain rice and malted rice, resulting in the final product: mackerel heshiko narezushi. In the past, every family made their own.” Morishita added that he enjoyed this dish since he was a child. He also showed us his heshiko shed, the building where he actually makes heshiko.

Mr.Morishita still makes heshiko the traditional way in his heshiko shed, and all the necessary tools are on display there, including wooden barrels, stone weights, and plaits woven from straw. He tells us that heshiko gets its name from how it’s made. Fishermen ferment fish in barrels and use stone weights to “heshikomu” (pack down) the fish.

The process of making mackerel heshiko 

Mackerel heshiko is made from autumn to early spring, using mackerel that has put on fat for the winter.

Morishita explains: “First, I cut the mackerel open from the back and gut it, then immediately put it in ice water. Blueback fish such as mackerel must be kept fresh above all else. Next, I cut off the meat that is still red with blood and rinse it in fresh water. I stuff the rinsed mackerel with salt, a task that requires sensibilities refined over many years. Then I put the mackerel into a barrel and put the inner lid on it when it reaches the top. Finally, I put a stone weight on top and let it ferment for one to ten weeks.”

The barrel is bowl shaped, so it has a broad top and a narrow bottom. That is why Morishita uses straw plaits, to spread force out evenly and keep any gaps from forming.

“The next step in the process is called nukaoshi. I start by laying a bed of rice bran that covers the floor and sides of the barrel, then cover it with alternating layers of fermented mackerel and rice bran, and let this ferment for a few months to a year. The umami flavor contained in the mackerel leeches into the water, and I keep that in there to pickle it all together,” says Morishita.

He shows us the barrel where it is being pickled, which is indeed filled with light brown water up to the brim. This water contains the umami flavor. In recent years, heshiko has also attracted attention as a method for extracting umami flavor.

Morishita makes heshiko using only salt and rice bran, with no unnecessary ingredients. The summer heat accelerates fermentation, and the harsh cold of winter does the same for maturation.

He tells us that, “as this process of fermentation and maturation continues, the lactic acid bacteria contained in the rice bran bed breaks down the protein in the fish, giving the heshiko its distinctly strong flavor and aroma.”

Mature heshiko turns a lovely brown color and produces a sweet smell. The mackerel heshiko, even served on its own, has an excellent umami flavor and a rich aroma. When cooking at home, it is served on piping hot rice, in a soup of boiled rice with tea, or grilled over charcoal and served with sake. It can be enjoyed in many different ways.

Heshiko narezushi

Once the heshiko is ready, it is used to make narezushi. The strongly salted heshiko is then put in fresh water to leech out some of the salt. 1.5 kg of plain rice and 750 g of malted rice are mixed together, then stuffed inside the skinned heshiko. This is put back in the barrel with the stone weight on top, and it is all left to pickle for two more weeks. Finally, the narezushi is ready! 

Mackerel narezushi, pickled in plain rice and malted rice, is viscous like yogurt. Its appearance may be off-putting, but if you are brave enough to take a bite, you will be pleasantly surprised by its superbly sour and mildly sweet flavor. All the work put in to narezushi packs it full of umami flavor, and the plentiful lactic acid bacteria are said to be good for both the function of the intestines and ensuring beautiful skin. It is one of the finest fermented foods that Japan has to offer.

Mr. Morishita tells us that, “the mackerel catch has always been good in this area. It was wise of our people back then to not only send fish to the capital, but to preserve that fish well and prepare it in many delicious dishes. I think that’s what led to preserved foods such as heshiko and narezushi. These foods take a lot of time and work to prepare, so I am really impressed that my ancestors could come up with them in the first place. I hope that everyone has a chance to enjoy them.” 

It is said that this land once had such massive catches of mackerel that they were thought to have sprung up from the bottom of the sea. In 1974, the catch landed at Tagarasu in Obama alone was 3,580 tons – a truly impressive number!

In recent years, over-fishing and other factors have caused the catch of mackerel to decrease nationwide, and the catch in Tagarasu District has also decreased drastically compared to the past. Faced with these problems, the locals have undertaken a new initiative to breed mackerel. 

In 2006, mackerel narezushi was recognized by the Slow Food Foundation for Biodiversity in Italy as “a traditional food or ingredient deeply tied to a region and its people but in danger of disappearing”, and collected by the Ark of Taste as a world heritage food.

The fermented mackerel narezushi is one of the pinnacles of Japanese food culture, and the tradition of making it is carried on to this day by the local people, who wish to pass on the wisdom of their ancestors and this proud food culture to later generations.