Japanese short grain rice or the japonica rice is widely grown in Japan.They are short and round compared to other rice in the world. When cooked properly they should be soft and chewy and have a faint sweet taste.
Japanese Short Grain Rice Japanese Medium Grain Rice
Japonica rice are grown in the United States as well, but the majority of them are the medium grain japaonica rice and they are not as chewy as the short grain rice.
Recently more short grain japonica are beginning to be cultivated in the United States, and for an extra 50 cents per pound, it is recommended to use the short grain version to make sushi. They are usually labeled premium as short grain.