Naiju' originally meant the middle and low ranked court officials and government officials who were in charge of miscellaneous affairs and guard in the Imperial Palace, which were gradually organized into a leading agency 'Naijusho' (内豎所) to be established.
内豎は元々内裏の雑務や警備を担当する童子や中小役人の事を指していたが、次第に組織化されて内豎所という統率機関が設置されていた。