The Yayoi people were the first proper farmers in Japan. From almost the very beginning of the Yayoi period, they built sophisticated wet rice (paddy) fields with canals and dams. They had the advanced know-how and farming techniques, brought over from Asian mainland with immigrants. For a long time, these immigrants were thought to have arrivals from the Korean peninsula, but recently, there has also been compelling DNA evidence to suggest that at least some of the immigrants came from the Jiangsu region of Chinese mainland. Japan was one of the last of Asian countries to adopt rice agriculture, some seven to eight thousand years behind China.