Although not definite, it is more likely that the sushi name came to Japan from Southeast Asia or China. There are traces back as early as 500B.C. when mountain people of Southeast Asia used river fish and and rice to preserve the fish through pickling and fermenting. A similar fermenting process was used in China but it became obsolete during Mongolia's reign over China in the 14th to 17th Centuries.

Thus in Japan, sushi was originally a way of preserving fish by using rice and being left to ferment up to a year. In this process, only the fish would be eaten and the rice thrown away. Over time, methods of fermentation were developed that only took a few days.

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