Where does the Japanese food okayu originate from?

Question:

I have to do an assignment for Japanese and we have to find 3 foods from Japan and explain where they originate from. I chose Okayu but I can't find where it comes from, maybe you could just tell me where it's mainly eaten?

Answer:

お粥 (okayu) -- is a Japanese form of congee served to invalids and is often an infants first food. Congee, the food, was prevalent in China as early as the pre-Qin period (221 - 207 B.C.) and may have originated there. The congee recipes used in India show Chinese influence. The origin of the food is somewhat confused as the word "congee" itself is believed to have originated with the Dravdian people of India.