The main idea in the preparation of sushi is the preservation and fermentation of fish with salt and rice, a process that has been traced back to
Southeast Asia where fish and rice fermentation dishes still exist today. The science behind the fermentation of fish in rice is that the vinegar produced from the fermenting rice breaks the fish down into
amino acids. This results in one of the five basic tastes, called
umami in Japanese.
[3] 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".
Modern 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 (1336–1573) of Japan,
vinegar was added to the mixture for better taste and for 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 the rice were pressed using wooden (usually bamboo) molds. By the mid 18th century, this form of sushi had reached
Edo (contemporary
Tokyo).
[4]Sushi by
Hiroshige in
Edo periodThe 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 (it was therefore prepared quickly) and could be eaten with one's hands roadside or in a theatre.
[4] Originally, this sushi was known as Edomae zushi, because it used freshly caught fish in the Edo-mae (Edo Bay or
Tokyo Bay). Though the fish used in modern sushi no longer usually comes from Tokyo Bay, it is still formally known as Edomae nigirizushi.
Types of sushi
Types of sushi
The common ingredient across all the different
kinds of sushi is
sushi rice. The variety in sushi arises from the different fillings and toppings, condiments, and the way these ingredients are put together. The same ingredients may be assembled in a traditional or a contemporary way, creating a very different final result.
[5]Nigiri-zushi 
Nigiri-zushi
Nigiri-zushi (握り寿司, lit. hand-formed sushi). This is the most typical form of sushi in restaurants[
citation needed]. It consists of an oblong mound of sushi rice that is pressed between the palms of the hands, sometimes with a speck of
wasabi and a slice of fish called neta draped over it. Certain fish is typically bound to the rice with a thin strip of nori, most commonly tako (octopus), unagi (freshwater eel), anago (sea eel), ika (squid), and tamago (sweet egg). Nigiri is generally served in pairs.
Gunkan-maki (軍艦巻, lit. warship roll). A special type of nigiri-zushi: an oval, hand-formed clump of sushi rice that has a strip of "nori" wrapped around its perimeter to form a vessel that is filled with some soft, loose or fine-chopped ingredient that requires the confinement of nori such as
roe,
natto, oysters, sea urchin, and quail eggs. Gunkan-maki was invented at the
Ginza Kyubey (Kubei) restaurant in 1931;
[6][7] its invention significantly expanded the repertoire of soft toppings used in sushi.
Temarizushi (手まり寿司, lit. ball sushi). It is a ball-shaped sushi made by pressing rice and fish into a ball-shaped form by hand using a plastic wrap. They are quite easy to make and thus a good starting point for beginners.
[8]Maki-zushi (roll)

Rolling maki
Maki rolls
Makizushi (巻き寿司, lit. rolled sushi). A cylindrical piece, formed with the help of a bamboo mat, called a
makisu (巻き簾). Makizushi is generally wrapped in nori, but can occasionally be found wrapped in a thin
omelette, soy paper, cucumber, or parsley. Makizushi is usually cut into six or eight pieces, which constitutes a single roll order. Below are some common types of makizushi, but many other kinds exist.
Futomaki (太巻き, lit. large or fat rolls). A large cylindrical piece, with nori on the outside. A typical futomaki is three or four centimeters (1.5 in) in diameter. They are often made with two or three fillings that are chosen for their complementary tastes and colors. During the
Setsubun festival, it is traditional in
Kansai to eat uncut futomaki in its cylindrical form. Futomaki is generally vegetarian, but may include toppings such as tiny fish eggs.
Hosomaki (細巻き, lit. thin rolls). A small cylindrical piece, with the nori on the outside. A typical hosomaki has a diameter of about two centimeters (0.75 in). They generally contain only one filling, often tuna, cucumber,
kanpyō, thinly sliced carrots, or, more recently, avocado.
Kappamaki, (河童巻き) a kind of Hosomaki filled with cucumber, is named after the Japanese legendary water imp fond of cucumbers called the
kappa. Traditionally, Kappamaki is consumed to clear the palate between eating raw fish and other kinds of food, so that the flavors of the fish are distinct from the tastes of other foods.
Tekkamaki (鉄火巻き) is a kind of Hosomaki filled with raw tuna. Although some believe that the name "Tekka", meaning 'red hot iron', alludes to the color of the tuna flesh, it actually originated as a quick snack to eat in gambling dens called "Tekkaba (鉄火場)", much like the
sandwich.
[9][10]Negitoromaki (ねぎとろ巻) is a kind of Hosomaki filled with
scallion and chopped tuna. Fatty tuna is often used in this style.
Tsunamayomaki (ツナマヨ巻) is a kind of Hosomaki filled with canned tuna tossed with
mayonnaise.
Temaki (手巻き, lit. hand rolls). A large cone-shaped piece of nori on the outside and the ingredients spilling out the wide end. A typical temaki is about ten centimeters (4 in) long, and is eaten with fingers because it is too awkward to pick it up with
chopsticks. For optimal taste and texture, Temaki must be eaten quickly after being made because the nori cone soon absorbs moisture from the filling and loses its crispness and becomes somewhat difficult to bite.
Uramaki (裏巻き, lit. inside-out rolls). A medium-sized cylindrical piece, with two or more fillings. Uramaki differs from other maki because the rice is on the outside and the nori inside. The filling is in the center surrounded by nori, then a layer of rice, and an outer coating of some other ingredients such as roe or toasted
sesame seeds. It can be made with different fillings such as tuna, crab meat, avocado, mayonnaise, cucumber, carrots.
Makizushi selection (Futomaki and Inarizushi at right) from a
Kansai Super store.
Oshizushi 
Oshizushi (押し寿司, lit. pressed sushi). A block-shaped piece formed using a wooden mold, called an
oshibako. The chef lines the bottom of the oshibako with the toppings, covers them with sushi rice, and then presses the lid of the mold down to create a compact, rectilinear block. The block is removed from the mold and then cut into bite-sized pieces. This variety originates from the
Kansai Region and is a favourite and specialty of
Osaka.
Inari-zushi
Wikibooks Cookbook has an article on
InarizushiInari-zushi (稲荷寿司, stuffed sushi). A pouch of fried tofu filled with usually just sushi rice. It is named after the Shinto god
Inari, who is believed to have a fondness for fried tofu. The pouch is normally fashioned as deep-fried tofu (油揚げ, abura age). Regional variations include pouches are made of a thin omelet (帛紗寿司, fukusa-zushi or 茶巾寿司, chakin-zushi) or dried gourd shavings (干瓢,
kanpyō). It should not be confused with inari maki, which is a roll filled with flavored fried tofu. A very large version, sweeter than normal and often containing bits of carrot, is popular in Hawaii, where it is called "cone sushi."
Chirashizushi
Chirashizushi

Chirashizushi (ちらし寿司, lit. scattered sushi). A bowl of sushi rice with other ingredients mixed in (also refers to barazushi). It is commonly eaten in Japan because it is filling, fast and easy to make. Chirashizushi most often varies regionally because it is eaten annually as a part of the Doll Festival, celebrated only during March in Japan.
Edomae chirashizushi (
Edo-style scattered sushi) is an uncooked ingredient that is arranged artfully on top of the sushi rice in a bowl.
Gomokuzushi (Kansai-style sushi). Cooked or uncooked ingredients mixed in the body of rice in a bowl.
Chirashizushi is a favorite because the ingredients are often chef's choice. The better you know your sushi chef, the more exotic your ingredients are likely to be.
Narezushi (old style fermented sushi)
Narezushi (熟れ寿司, lit. matured sushi) is an older form of sushi. Skinned and gutted fish are stuffed with salt, placed in a wooden barrel, doused with salt again, and then weighed down with a heavy
tsukemonoishi (pickling stone). They are supposedly salted for ten days to a month, then placed in water for 15 minutes to an hour. They are then placed in another barrel, sandwiched, and layered with cooled steamed rice and fish. Then the mixture is again partially sealed with
otoshibuta and a pickling stone. As days pass, water seeps out, which must be removed. Six months later, this funazushi can be eaten, and remains edible for another six months or more.
Funazushi (鮒寿司) is a dish in Japanese cooking, which involves with anaerobic
lacto-fermentation of fresh water fish, funa (
鮒,
crucian carp). The dish is famous as a regional dish from
Shiga Prefecture, It is considered to be a
chinmi, a delicacy in Japanese cooking.
[11]Western Sushi
The types of sushi rolls typically found in the west are rarely found in Japan. This is typically thought of as an invention to suit the American palate,
[12]. The increasing popularity of sushi in North America, as well as around the world, has resulted in numerous kinds of uramaki and regional off-shoots being created, such as the
California roll, the B.C. roll (grilled salmon skin), and the
Philadelphia roll (
cream cheese). The following are lists of typical ingredients in universally popular rolls.
The caterpillar roll generally includes avocado,
unagi,
kani kama (imitation crab stick), and cucumber.
The dynamite roll includes yellowtail (hamachi), and fillings such as bean sprouts, carrots, chili and spicy mayo.
The rainbow roll is typically a California roll topped with several various
sashimi.
The spider roll includes fried
soft shell crab and other fillings such as cucumber, avocado, daikon sprouts or lettuce, roe, and spicy mayonnaise.
A Philadelphia roll almost always consists of smoked salmon, cream cheese, cucumber, and/or onion.
A Peckham roll consists of foie gras, toro and avocado. It is presented as a handroll.
A BC roll has grilled salmon with sweet sauce and cucumber. It is named after
British Columbia for its famous wild
Pacific salmon.
A crunchy roll is typically a California roll with shrimp
tempura wrapped inside with the other ingredients, with the outside of the roll coated with fried tempura batter crumbs. It is often topped with sweet eel sauce or chili sauce.
Other rolls may include
scallops, spicy
tuna,
beef or
chicken or
teriyaki roll,
okra,
vegetables, and
cheese. Sushi rolls can also be made with
Brown rice and
black rice. These have also appeared in Japanese cuisine.