Ancient rice is called Kodai-mai in Japanese. This rice has features inherited wildness from original species of rice.
I am not certain when ancient people started growing ancient rice in Japan. However, what I can say for sure that ancient rice is exactly original breed of modern rice.
Features of ancient rice
Ancient rice generally has vigorous characteristic itself compare to other kinds of rice. This type of rice can sustain and able to grow on the waste land without any fertilizer and chemicals. And further, they are able to grow under bad circumstance such as drought and in cold water. However, its quality is sometimes good and sometimes bad and the quantity of the harvest is not as same as modern rice annually. Adding that, they are easily to fall down due to its tall straw. That is why they have hardly been grown in these days.