You know dining habits have shifted dramatically when Iowa City’s Sushi Kicchin boasts a four-and-a-half star Yelp review.

From pinwheel-shaped rainbow rolls to minimalist slices of toro pressed gently on rice, the idea of serving raw fish has spread far and wide, prepared by everyone from trained sushi masters, to commissary workers who keep your local Duane Reade stocked with California rolls.

As pervasive as it is today, sushi didn’t come into existence until the 20th century; eating raw fish over rice only became a practice once refrigeration was invented in 1913.

The most primitive form of sushi would probably send most contemporary eaters running. “It smelled really bad,” says Yoko Isassi, an L.A.-based Japanese cooking instructor whose done extensive research on history of sushi. “Today’s sushi is a very new concept.”

Born in the Gifu prefecture in central Japan, Isassi initially immigrated to America to become an architect. She eventually gave up on that to teach Japanese cooking classes, informed by her travels in her home country.

“Back then, it was just pickled fish and rice, which would be left in a barrel for a year and weighed down by a heavy stone,” she explains. Called nare-sushi, the original form of sushi can be traced back to Southeast Asia in 3-5 century B.C., when people first began the practice of fermenting fish with salt and rice.

“There are a lot of similarities between the ethnic tribes of southeast China and the Japanese people,” Isassi says. “Because of this, there’s speculation that a certain chunk of people from southern China emigrated to Japan and heavily influenced the food culture.”

The product that we see at our local sushi bars has undergone various stages of transformation to arrive where it is today. “Each new generation of sushi reflects the attitudes of its time,” says Isassi.

Why, then, were prime cuts like fatty tuna initially discarded and used as fertilizer? And how did vinegar come into the equation? To answer these questions—and learn about how rampant wildfires played a crucial role in sushi’s development—we asked raw-fish expert Yoko Isassi to give us a generation-by-generation history lesson on the art of sushi making.

FIRST GENERATION: NARE-SUSHI

Basically: Barrel-fermented fish with rice. Rice is scraped off. Only the fish is eaten.

Originated: 3rd century B.C. in Southern China

Preparation time: 1 year

Where to get it today: Regions near Lake Biwa

The very first generation of sushi involved an intensive fermentation process.“After rainy seasons in southern China and parts of Japan, the lakes would flood and the fish would get caught in the rice fields,” Isassi says. “Pickling was a way to preserve the excess fish.”

While documentation of this practice is sparse, Isassi notes that the character for pickled fish with salt, si 鮨, appeared in the Chinese dictionary as early as the 3rd to 5th century B.C. Then in the 2nd century A.D., the character sa 鮓 appeared, which translates to pickled fish with salt and rice. This created the foundation for sushi. “The fish of choice was most commonly carp,” says Isassi. “They would take the fish, gut it, rub it with salt, and pickle it in a wooden barrel for a few months. Then after that, they would scrape the salt off and then stuff the belly with rice.”

Dozens of rice-stuffed fish would be packed in a wooden barrel and then weighed down with a heavy stone. The fish would sit for a year before being cracked open for consumption. “No one ate the rice back then. It was just the fish.” This practice spread to Japan but eventually went out of vogue in China after northern nomadic tribes invaded and ruled the area. “Even today, this style can still be found in some parts of Yunnan and northern Thailand,” Isassi says.

SECOND GENERATION: HAN-NARE SUSHI



Basically: Barrel-fermented fish with rice

Originated: Before the14th century in Japan

Preparation time: 1-4 weeks

Where to get it today: Wakayama

The only difference between the process of making han-nare sushi and thenare-sushi is the fermentation time. “Instead of a year, the barrels would be cracked open within the month,” Isassi says.

And instead of discarding the rice, people would actually eat it with the fish. “The rice had a sour taste to it because of the presence of lactic acid,” she says. “At this time, people really began to appreciate the taste of it, most likely because the vinegar industry had exploded in Japan in the 13th century.”

THIRD GENERATION: HAYA-NARE SUSHI



Summary: Box-pressed cured fish over vinegar-seasoned rice

Originated: 14th-18th century Japan

Preparation time: Hours to a couple of days

Where to get it today: Osaka, Nara, Kyoto, Toyama

By the 18th century, the process of sushi-making shortened dramatically, taking only a couple of days compared to the yearlong process of prior generations. “Instead of waiting for lactic acid to naturally develop on the rice, people started to add vinegar to the rice to mimic the sourness,” Isassi says. The rice would be packed underneath slices of cured or cooked fish, then pressed with a wooden box for hours—sometimes days—at a time. “Fish still had to be treated,” Isassi notes. “They did it either through pickling, curing, or just simply cooking it.”

Every prefecture developed its own style of box-pressed sushi. “In Kansai, for example, they used kombu (kelp) to cook the rice, and seasoned it with vinegar and sugar,” she says. “In Nara, people used persimmon leaves to wrap the sushi. In Toyama, they used bamboo leaves. Adding sugar to the rice was a common practice to preserve the longevity of the sushi.”

FOURTH GENERATION: EDO-MAE SUSHI



Basically: Pre-cured fish over vinegar-seasoned rice. Packed with hands.

Originated: 19th century to early 20th century in Edo (modern-day Tokyo)

Preparation time: Within a few hours to half a day

Where to get it today: Tokyo

The fourth generation of sushi developed in modern-day Tokyo. “Because Edo [the former name of Tokyo] was really dense, they often dealt with fires,” Isassi explains. “They’d appear every several years. To extinguish the flames and stop them from spreading, they would have to knock down all the houses.”As a result, hordes of blue-collar workers flocked to the street to help with the rebuilding process. “That’s how the culture of street food in Japan started,” Isassi says. “They would use fish from the Edo bay, quickly cure it, and serve it over packed vinegar-seasoned rice.”

Isassi notes that only certain fish were consumed. “They used to discard fatty tuna on the fields for fertilizers. There just wasn’t a way to properly treat these cuts. Remember, there wasn’t refrigeration.” The first varieties of Edo-maesushi were also three times bigger than modern-day sushi slices. “It was basically a gigantic rice ball with fish. As time went on, the portion sizes got smaller and smaller,” says Isassi.

FIFTH GENERATION SUSHI: MODERN-DAY SUSHI

Basically: Raw fish over rice, inside-out rolls, conveyer belt sushi

Originated: 20th century

Preparation time: Instant

Where to get it today: Global

The invention of refrigeration in the 20th century changed the sushi scene forever. This is when raw fish slices over rice came into vogue, and sushi morphed from a humble foodstuff into a luxury experience. “In Japan, eating sushi is usually reserved for special occasion meals,” Isassi says. “My family and I rarely went out for it because it was expensive.”

Sushi soon began to spread globally and in the 1960s, the United States came up with its own rendition: the inside-out roll, which was invented in Los Angeles in the 1960s, followed by conveyor-belt sushi, which peaked in the 1980s.

More from First We Feast:

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Watch This Incredible Japanese Chef Make Micro-Sized Sushi (Video)

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Andy Milonakis Goes on Rant About L.A. Sushi, Thinks New York’s Sushi Scene is Far Superior