However sites with concentrated evidence of bronze ware manufacturing, such as those in northern Kyushu, have not yet been found and its manufacturing and distribution system remain unsolved.
しかし、北部九州ほど青銅器生産の証拠が集中して発見される遺跡は未だ見つかっておらず、その生産体制や流通体制などには未解明の部分が多い。