Sushi, arguably the most minimalistic dish ever created, has also become complicated and diverse. Nothing seems to epitomize simplicity as much as nigirizushi, a single slice of fish over rice. Sushi rolls (makizushi, also known as norimaki) were also once as simple, with only prosaic ingredients such as dried gourd (kanpyō) rolled up with rice into a tube of nori. But today practically anything can be stuffed into a sushi roll or spread on top: fried shrimp, cream cheese or Spam. Sushi rolls can be made ‘inside out’ with the rice on the exterior. The rolls are also sometimes breaded and fried. They can be topped with slices of fish, prawns, avocado, fried Japanese breadcrumbs or fried onions. Sometimes they are slathered with different colours of sauce. In short, what was once a lean food of green cylindrical geometry has become, in some instances, an amorphous dripping creature with twice the calories, sodium and cholesterol of a McDonald’s hamburger.

Such sushi experimentation might seem new, and inauthentic to some self-described sushi purists, but chefs have been tinkering with the recipe for sushi for millennia. The earliest Chinese examples of sushi, which date from the sixth century, flavoured the rice and fish with orange peel and ‘wine’ made from grains. One eighteenth-century cookbook in Japan suggested using the skin of the poisonous Japanese blowfish (fugu) or paper instead of nori for makizushi – the paper was discarded before eating the roll. Besides the California roll, which is often scorned by sushi purists as ‘inauthentic’, there are other ‘local’ sushi in North America such as the San Francisco roll (made with cucumber, salmon, salmon roe and fresh basil), the Las Vegas roll (shrimp, eel and cream cheese), the Texas roll (freshwater eel, avocado and smelt eggs), which is of course fried, and the Philadelphia roll (cream cheese, smoked salmon, cucumber and avocado). Hawaii, Alaska, New York and Canada have their named rolls as well. The New York roll, for instance, contains pastrami. Sushi rolls have also become supersized to birth the ‘sushi burrito’. Sushi bagels, sushi burgers and sushi pizza are all foods that substitute sushi rice for bread and reconstruct the rolls into new shapes. Leaving America, one finds Prague sushi, a nigirizushi of tuna marinated in soy sauce and beer and topped with apple slices. Sushi rolls drenched in panko and fried like tempura before being accented with chilli sauce are popular in South America. The Bratislava roll contains bacon, red pepper, chives and the spicy sheep’s cheese bryndza. In 2010 I was surprised to find ‘Korean Sushi’ on the menu of a Tibetan restaurant in Dawu, Qinghai, China, which turned out to be makizushi stuffed with Spam.

Toppings and fillings may change, but rice is common to all the aforementioned sushi; however, there are types of sushi in Japan that do not use rice at all. Several Japanese cookbooks from the early modern period (defined as the Edo or Tokugawa period, 1600–1868) provide recipes for riceless sushi that substitute the lees (okara) left over from making tofu. Once the soybeans have been heated and pulverized to extract soy milk to make tofu, the leftover soy lees can be chopped, pan-fried, flavoured and mixed with finely diced vegetables, burdock and mushrooms. Assemblage of Noted Grain Dishes (Meihan burui), published in 1802, indicates that the okara should be mashed, stir-fried in oil and flavoured with Japanese pepper (sanshō) before being used as a stuffing for fish. The text even goes so far as to suggest that the fish could be grilled if it smells too fishy. As we can see from this recipe, the word ‘sushi’ did not necessarily designate a food that was eaten cold, or while the fish was still fresh, or that automatically included rice; indeed, in the earliest recipes for sushi, the rice (or other grain) was probably discarded instead of being eaten after its role in fermentation was finished.

THE EARLIEST SUSHI

While it is hard to determine a shared characteristic among all of the various types of sushi available today, what designated the first sushi was neither the use of fish nor rice but the taste, and the taste of sushi may be the origin for its Japanese name. Sushi can be written several different ways in Japanese: the phonetic すし and by the two characters 寿司, which when put together might mean ‘felicitous rule’ but instead are used solely for their sounds. The combination 寿司 (and its variation 寿し) date to the early modern period, a time when the Japanese developed visual and verbal puns into a popular art form.9 Two earlier ways of writing sushi as 鮨 and 鮓 originated in China. The first character, pronounced as zhi in Chinese, originally referred to a fermented dish made from salt and fish, according to China’s oldest dictionary, the third-century BCE The Literary
Expositor (Erya). China’s third oldest dictionary, the third-century CE Explanation of Names (Shiming), defines the second character – pronounced zha in Chinese – as fish preserved in salt with rice. Both dishes were fermented foods using salt and fish, and their similarity eventually led writers to use them interchangeably. Later in the third century CE they were considered synonyms, referring to a fermented rice and fish dish that is the prototype of the modern sushi known today. When these characters arrived in Japan, the Japanese likewise made no distinction between them and pronounced both as ‘sushi’, according to Japan’s earliest Chinese–Japanese dictionary, compiled around the year 900.

But why did the Japanese call it sushi? When the Japanese adopted Chinese characters, they typically retained the original Chinese pronunciation and also applied the characters to an existing Japanese word to create a Japanese reading. According to one hypothesis that dates to at least the end of the seventeenth century, the Japanese word ‘sushi’ was derived from the word sui, meaning ‘sour tasting’. The fact that the earliest recipes for sushi produced sour and pungent-tasting dishes adds credence to the theory that the word ‘sushi’ designated a sour food. Indeed, one of the ancient Chinese ways of writing sushi (zha), combines the character for fish (魚) with the one for vinegar (乍), suggesting a sour-tasting fish.

Modern sushi also has a very slight sour taste because the rice is flavoured with vinegar. Vinegar became a sushi ingredient in the seventeenth century, around the time that Japanese philologists theorized that the Japanese word ‘sushi’ took its name from its sour taste. However, the earliest surviving recipes for sushi, such as the ancient Chinese examples mentioned earlier, did not rely on vinegar. The sour taste of the sushi derived from lactic-acid fermentation.

Thus two kinds of sushi exist. The first, and earliest, are sushi that are sour owing to lactic-acid fermentation, and the second are sushi that have a slightly sour taste because of the addition of vinegar. These are the two major categories of sushi, and the history of sushi can be told, as it is in this book, as the story of a transition away from the ancient method of lactic-acid fermentation to other techniques, such as using vinegar. Sushi thus evolved from a method to preserve fish (and other animal proteins) using fermentation to a means of simply serving fish with rice with a slight vinegary taste.

Both sushi flavoured with vinegar and sushi using lacticacid fermentation rely on rice (or another grain), but in different ways. Rice flavoured with vinegar (and usually salt and sugar as well) plays a key role in the taste and mouthfeel of nigirizushi and makizushi. It provides a backdrop for appreciating the fish. Some sushi experts judge the quality of sushi restaurants largely on how well the rice is prepared.14 In contrast, the taste of the rice in lactic-acid sushi is secondary to its main function as a medium for fermentation. Rice contains starch, which breaks down into glucose. Lactic-acid bacteria feed on the glucose to produce lactic acid, which transforms food. First, it acts as a preservative. Lactic acid lowers the pH of the perishable food and inhibits the growth of microbes that could cause diseases or could otherwise contaminate the end product. Second, lactic acid imparts tartness. Lactic-acid fermentation is the reason why yoghurt has a sour taste. Finally, lactic-acid fermentation breaks down the proteins in animal or fish flesh into amino acids. If the process continues for long enough, it will also render the bones soft enough to eat.16 In contrast to sushi that rely on vinegar, which are best eaten immediately after they are made, lactic-acid fermentation takes time. Some examples of lactic-acid sushi can take up to two years or more to reach their peak flavour. One of these is funazushi, which can be made in a few months, but three- or five-year-old examples are especially prized by funazushi fans.