According to "Gishiwajinden" (literally, an 'Account of the Wa' in "The History of the Wei Dynasty"), even Naokoku in the third century had 20,000 families (had a population of over 100,000), which was much larger than the population of Fujiwara-kyo or Heijo-kyo.
『魏志倭人伝』によると3世紀の奴国（博多）でさえ2万戸（10万人以上）の人口があり藤原京や平城京より遥かに人口が多かった。