Japanese rice is a shorter grain that tends to be a little sticky. Japan also has a special variety of rice called mochigome（もち米）that is even stickier. Moshigome is used to make special foods such as mochi (Japanese rice cake). Sushi rice is regular Japanese rice with sushi vinegar added.
Outside of Japan most Japanese restaurants do not serve Japanese rice. This is one of the reasons many Japanese diners do not like the taste of Japanese food outside of Japan. However, some California rice farms are now growing Japanese style rice that is making inroads with Japanese customers.