According to "Kogo-shui" (History of the Inbe clan), Okura (a government treasury) was set up to accommodate the increasing number of gifts presented from regions throughout the nation in the era of Emperor Yuryaku.
『古語拾遺』によれば、雄略天皇代、増大する諸国からの貢物に対応すべく、新たに大蔵が興された。