Sushi as we know it today evolved out of efforts to find ways to preserve fish. It was discovered that the natural fermentation process of rice worked to preserve fish. Soon, in order to speed up the preservation, vinegar was poured over the rice with the fish atop it - an Edo Period innovation. Today, variations in sushi abound and creative departures seem to be the order of the day, yet the following styles of sushi are seen as the loci:
Gunkanmaki: In this sushi preparation, a knob of sushi rice is wrapped in nori and topped with seafood, usually fish roe.
Inarizushi: In this simple preparation, pouches of deep-fried tofu are filled with sushi rice.
Makizushi: This is a rolled sushi in which a fish or vegetable filling is enclosed in a layer of sushi rice and an outer layer of nori seaweed.
Nigirizushi: This type of sushi consists of a bite-sized topping, usually raw seafood, above a knob of sushi rice.
Temakizushi: This no-fuss sushi consists of nori cones filled with sushi rice and accompaniments such as vegetables and seafood.
Temarizushi: This ball-shaped sushi is named after its resemblance to traditional thread decorations known as temari.