To find the origins of sushi we must look at a dish called narezushi. Narezushi is salted fish stored in fermented rice for months at a time. Southeast Asia and Japan both had their own version of the dish, the rice was discarded and the fish was eaten. This was the first iteration of sushi and was seen by the Japanese as an important source of protein.

In the Edo Period, between 1600 and 1800 in Japan, sushi as we know it was established. Fish and vegetables were wrapped in rice and mixed with vinegar. Much like with Narezushi, each region had its own variations to it, but this is close to the version most people in today’s world are familiar with. In the early 1800s, the style of nigirizushi began to emerge. This consisted of a mound of rice with a slice of fish draped over it.

The Great Kanto earthquake in 1923 disrupted the Japanese economy and it displaced many people from Edo Japan. Japanese people were forced to restart their lives in new places and this consequently took sushi all over the world.

In the U.S., sushi was emerging from communities in Little Tokyo by the mid-twentieth century. It became popular among Hollywood celebrities which led to it gaining the public’s attention. What was once foreign to Americans became Americanized with the California roll that used crab and avocado instead of raw fish. In 2009, International Sushi Day was proclaimed on June 18. The idea came from Facebook and it took on a life of its own.

Resource: https://nationaltoday.com/international-sushi-day/