The origins and affinities of Japanese were analysed by means of cluster analysis using nine cranial measurements which were statistically selected as those representing a large proportion of the variance. As a result, the following hypotheses are proposed: Japanese are basically descendants of Jomon people, a fairly large amount of admixture between migrants from the Korean Peninsula and Jomon people took place during the Yayoi and protohistoric ages, particularly in western Japan, the migrants were close to north Asians in cranial morphology, Ainu and Ryukyus (Okinawan people) seem to be direct descendants of Jomon people without any or with very little influence of the migrants and geographical variations in modern Japanese quite likely are the result of differences in the magnitude of admixture.