Question: In which way are toppings served in sushi?
About the article "Sushi", section "Nigirizushi".

Candidate passages:
Sushi pizza is a variant of Japanese sushi served in Canada and the Northeastern US.
It uses a slightly crispy yet chewy fried rice patty as the base and is topped with a layer of sliced avocado, a layer of sliced salmon, tuna or crab meat, a drizzle of blended mayonnaise and wasabi powder and is served in wedges.
Nori, pickled ginger and roe are sometimes also served as toppings or sides.
The origins of Sushi Pizza are debatable but a Japanese sushi chef at Atami Sushi Restaurant in Montreal, Quebec, claimed in 1992 that she was the inventor of the dish.
Due to the popularity and wide availability of the dish in Toronto it has quickly become one of the city's signature dishes, along with the Peameal Bacon Sandwich. 
Unlike sashimi, which is almost always eaten with chopsticks, "nigirizushi" is traditionally eaten with the fingers, even in formal settings.
While it is commonly served on a small platter with a side dish for dipping, sushi can also be served in a "bento", a box with small compartments that hold the various dishes of the meal.
Soy sauce is the usual condiment, and sushi is normally served with a small sauce dish, or a compartment in the bento.
Traditional etiquette suggests that the sushi is turned over so that only the topping is dipped; this is because the soy sauce is for flavoring the topping, not the rice, and because the rice would absorb too much soy sauce and would fall apart.
If it is difficult to turn the sushi upside-down, one can baste the sushi in soy sauce using "gari" (sliced ginger) as a brush.
Toppings which have their own sauce (such as eel) should not be eaten with soy sauce.
Traditionally, the sushi chef will add an appropriate amount of wasabi to the sushi while preparing it, and etiquette suggests eating the sushi as is, since the chef is supposed to know the proper amount of wasabi to use.
However, today wasabi is more a matter of personal taste, and even restaurants in Japan may serve wasabi on the side for customers to use at their discretion, even when there is wasabi already in the dish. 
"Nigirizushi" (, "hand-pressed sushi") consists of an oblong mound of "sushi rice" that the chef presses into a small rectangular box between the palms of the hands, usually with a bit of "wasabi", and a topping (the "neta") draped over it.
"Neta" are typically fish such as salmon, tuna or other seafood.
Certain toppings are typically bound to the rice with a thin strip of "nori", most commonly octopus ("tako"), freshwater eel ("unagi"), sea eel ("anago"), squid ("ika"), and sweet egg ("tamago").
"Gunkanmaki" (, "warship roll") is a special type of "nigirizushi": 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, "nattō", oysters, "uni" (sea urchin roe), corn with mayonnaise, scallops, and quail eggs.
"Gunkan-maki" was invented at the "Ginza Kyubey" restaurant in 1941; its invention significantly expanded the repertoire of soft toppings used in sushi.
"Temarizushi" (, "ball sushi") is a ball-shaped sushi made by pressing rice and fish into a ball-shaped form by hand using a plastic wrap.
The common ingredient across all kinds of sushi is vinegared "sushi rice".
Variety arises from fillings, toppings, condiments, and preparation.
Traditional versus contemporary methods of assembly may create very different results from very similar ingredients.
In spelling sushi, its first letter "s" is replaced with "z" when a prefix is attached, as in nigirizushi, due to consonant mutation called rendaku in Japanese. 
Like many Japanese noodles, soba noodles are often served drained and chilled in the summer, and hot in the winter with a soy-based dashi broth.
Extra toppings can be added to both hot and cold soba.
Toppings are chosen to reflect the seasons and to balance with other ingredients.
Most toppings are added without much cooking, although some are deep-fried.
Most of these dishes may also be prepared with udon.