This paper reviews recent archaeobotanical evidence of the beginnings of rice and millet agriculture in prehistoric Japan, focusing on agricultural weed assemblages from early rice cultivation sites. In this study we show that the most reliable dispersal timing of rice and millet cultivation was the end of the Final Jomon period, corresponding to the Initial and Early Yayoi period of northern Kyushu. Rice and millet were introduced from China via Korea probably at the same time, as a pair. Early rice cultivation was likely practiced, not in slash-and-burn fields but in primitive paddy fields, which did not possess clearly defined paddy ridges or compartments, and were constructed in human-managed open wetlands near forests. Millets were probably cultivated on upland farmlands close to rice paddy fields. The use of berries and nuts which was the subsistence base of Jomon period continued during this time, and rice and millet agriculture gradually spread up until the Middle to Late Yayoi period.
