The original type of sushi, known today as nare-zushi (馴れ寿司, 熟寿司), was first developed in Southeast Asia and spread to south China before introduced to Japan sometime around the 8th century. Fish was salted and wrapped in fermented rice, a traditional lacto-fermented rice dish. Nare-zushi was made of this gutted fish stored in fermented rice for months at a time for preservation. The fermentation of the rice prevented the fish from spoiling. The fermented rice was discarded and fish was the only part consumed. This early type of sushi became an important source of protein for the Japanese.
The Japanese preferred to eat fish with rice, known as namanare or namanari (生成, なまなれ, なまなり). During the Muromachi period namanare was the most popular type of sushi. Namanare was partly raw fish wrapped in rice, consumed fresh, before it changed flavor. This new way of consuming fish was no longer a form of preservation but rather a new dish in Japanese cuisine.
During the Edo period, a third type of sushi was introduced, haya-zushi (早寿司, 早ずし). Haya-zushi was assembled so that both rice and fish could be consumed at the same time, and the dish became unique to Japanese culture. It was the first time that rice was not being used for fermentation. Rice was now mixed with vinegar, with fish, vegetables and dried foodstuff added. This type of sushi is still very popular today. Each region utilizes local flavors to produce a variety of sushi that has been passed down for many generations.
When Tokyo was still known as Edo in the early 19th century, mobile food stalls run by street vendors became popular. During this period nigiri-zushi (握り寿司) was introduced, consisting of an oblong mound of rice with a slice of fish draped over it. After the Great Kanto earthquake in 1923, nigiri-sushi chefs were displaced from Edo throughout Japan, popularizing the dish throughout the country.
Today the sushi dish internationally known as "sushi" (nigirizushi; Kantō variety) is a fast food invented by Hanaya Yohei (華屋与兵衛; 1799–1858) at the end of Edo period in today's Tokyo (Edo). People in Tokyo were living in haste even a hundred years ago. The nigirizushi invented by Hanaya was not fermented and could be eaten using the fingers or chopsticks. It was an early form of fast food that could be eaten in public or in the theater.