The Uchikura is thought to have existed around the period of Emperor Richu as a storage place to manage the Emperor's family's treasures and continued to exist as an institution within the Ministry of Central Affairs even after the Ritsuryo system started.
内蔵は履中天皇の時代に遡るとも言われ、天皇家の財宝を管理する倉庫で律令施行後も中務省の一機関として存続した。