Sushi was called NARE sushi in the seventh century. It was originally a way to preserve fish. The fish is salted and wrapped in rice. After the fish is fermented, the rice will produce lactic acid, so that the fish will be soaked to avoid spoilage. /kloc-in the middle of the 0/7th century, people added vinegar to sushi rice, which completely changed the making technology of sushi. This new method, also known as HAYA-SUSHI, can be made in half a day, because the acidity in vinegar accelerates the fermentation time and reduces the time for making sushi. About 200 years later, a sushi chef named Wu Yangping pressed sushi with his hands instead of stones, which was made by going up a flight of stairs. The art of sushi making, squeezed with his warm hands, and fermentation was almost completed at once. The method of making sushi now is still very similar to Wuyangping 200 years ago. Japan is a country whose staple food is rice. "Sushi rice" is a great pride of Japanese national food culture. Sushi is a unique food in Japanese cuisine. It is said that the method of making sushi was introduced into Japan from China together with rice planting technology. According to relevant data, sushi was mentioned in China's literary works as early as about 1 century, and sushi first appeared in Japanese literary works in18th century. At present, sushi shops in Japan are all over the world, so sushi has become a favorite food for people all over the world. There are many kinds of sushi, which can be divided into "Nama" cooked sushi, pressed sushi, hand-held sushi, pine sushi, stick sushi, rolled sushi, crucian sushi, etc. Among them, crucian sushi is considered to be the most famous and representative sushi made in Japanese cuisine according to the ancient method. However, sushi made by this ancient method is rare now. At present, most Japanese sushi is processed with vinegar mixed with rice, and because more than four seasonings are usually added to rice, sushi is also called "four-happiness rice".