Originally a hosho was a monjo (document), formed by senior vassals or magistrates, in order to certify orders issued by lords were formal and to instruct their prompt execution; in the Muromachi bakufu a hosho was made by kanryo (Shogun's Deputies) together with Shougun's order, the system of which was succeeded by the Edo bakufu.
奉書とは元々主君が出した命令書に対して、重臣や奉行などがその命令書が正規のものである証明とその速やかな執行を指示するために作成した文書であり、室町幕府では管領によって将軍の命令書とともに奉書が作成され、江戸幕府においてもこの制度を継承していた。