The traditional form of sushi is fermented fish and rice, preserved with salt in a process that has been traced to Southeast Asia, where it remains popular today. The term sushi comes from an archaic grammatical form no longer used in other contexts; literally, "sushi" means "it's sour", a reflection of its historic fermented roots.
The science behind the fermentation of fish packed in rice is that the vinegar produced from fermenting rice breaks the fish down into amino acids. This results in one of the five basic tastes, called umami in Japanese. The oldest form of sushi in Japan, Narezushi still very closely resembles this process. In Japan, Narezushi evolved into Oshizushi and ultimately Edomae nigirizushi, which is what the world today knows as "sushi."
Contemporary Japanese sushi has little resemblance to the traditional lacto-fermented rice dish. Originally, when the fermented fish was taken out of the rice, only the fish was consumed and the fermented rice was discarded. The strong-tasting and -smelling funazushi, a kind of narezushi made near Lake Biwa in Japan, resembles the traditional fermented dish.
Beginning in the Muromachi period (AD 1336–1573) of Japan, vinegar was added to the mixture for better taste and preservation. The vinegar accentuated the rice's sourness, and was known to increase its life span, allowing the fermentation process to be shortened and eventually abandoned. In the following centuries, sushi in Osaka evolved into oshi-zushi. The seafood and rice were pressed using wooden (usually bamboo) molds. By the mid 18th century, this form of sushi had reached Edo.
The contemporary version, internationally known as "sushi," was invented by Hanaya Yohei (華屋与兵衛; 1799–1858) at the end of Edo period in Edo. The sushi invented by Hanaya was an early form of fast food that was not fermented (therefore prepared quickly) and could be eaten with one's hands roadside or in a theatre. Originally, this sushi was known as Edomae zushi, because it used freshly caught fish in the Edo-mae (Tokyo Bay). Though the fish used in modern sushi no longer usually comes from Tokyo Bay, it is still formally known as Edomae nigirizushi.
【Shari】(Sumeshi) The common name for sushi rice with sweet and sour flavor.
【Neta】 Toppings and fillings.
【Murasaki】(Shouyu) The common name for soy sauce.
【Namida】(Wasabi) A piquant paste made from the grated root of the Wasabi japonica plant. True wasabi has anti-microbial properties and may reduce the risk of food poisoning. The traditional grating tool for wasabi is a sharkskin grater or samegawa oroshi. An imitation wasabi (seiyo-wasabi), made from horseradish and mustard powder and dyed green is common. It is found at lower-end kaiten zushi restaurants, in bento box sushi and at most restaurants outside of Japan. If manufactured in Japan, it may be labelled "Japanese Horseradish".
【Gari】 Sweet, pickled ginger. Eaten to both cleanse the palate and aid in digestion.
【Agari】(Ocha) In Japan, green tea is invariably served together with sushi. Better sushi restaurants often use a distinctive premium tea known as mecha. In sushi vocabulary, green tea is known as agari.
Conveyor belt sushi (kaiten-zushi, also called sushi-go-round, or kuru kuru sushi) is the popular English translation for Japanese fast-food sushi. In Australia, it is also known as sushi train (as the sushi goes around a track on a train, rather than a conveyor belt).
Kaiten-zushi is a sushi restaurant where the plates with the sushi are placed on a rotating conveyor belt that winds through the restaurant and moves past every table and counter seat. Customers may place special orders, but most simply pick their selections from a steady stream of fresh sushi moving along the conveyor belt. The final bill is based on the number and type of plates of the consumed sushi. Some restaurants use a fancier presentation such as miniature wooden "sushi boats" traveling small canals or miniature locomotive cars.