By the latter half of the seventh century, the power of Yamato sovereignty (Imperial court) had reached southern Kyushu but the ruling system was not yet perfected so that many groups of residents, called Kumaso or Hayato, defended their own local authority.
7世紀後半の九州南部はヤマト王権（朝廷）の勢力が及んでいたものの支配体制は完全ではなく、熊襲あるいは隼人と呼ばれる住民が多くの集団に分かれて割拠する状況であった。