The term Kanmon means written reports (Kanshin) for various information such as origins/precedents that were submitted by scholars, etc. at the request of the Imperial court. Such a survey was principally conducted by Geki (Secretary of the Grand Council of State), Jingikan (department of worship) and scholars of Shodo (various fields of academy) belonged to Daigaku-ryo (Bureau of Education under the ritsuryo system) or Onmyoryo (Bureau of Divination). Kanmon written by the scholars of Shodo were specifically called Shodo Kanmon.
In the event of a matter of national concern, the Imperial court ordered professional bureaucrats and scholars to submit Kanjin and used it as reference materials at Jin no sadame (ancient cabinet council) of Daijokan (Grand Council of State) and/or In no hyojo (consultation under the government by the Retired Emperor). Kanmon submitted by Tenyakuryo (the Bureau of Medicine) when the epidemic of smallpox occurred in 737 was recorded as a countermeasure in "Ruiju fusensho" (A collection of official documents dating from the years 737 to 1093). Other than the above, Tenmon Kanmon submitted at the time of Tenmon misso (reporting unusual astronomical phenomena to the emperor) and Myobo Kanmon submitted by scholars of law on the occasion of criminal cases are well-known. It was said that 200 volumes of 'Shodo kanmon' (written reports by various scholars from Daigaku-ryo and Onmyo-ryo) and 'Zoku shodo kanmon' (its number of volumes is unclear) were inherited by the Nakahara clan, which had the qualification of Tenmon misso at Geki. However, only two volumes of 'Shodo kanmon' that were compiled in "Gunsho ruiju" (Collection of historical documents compiled by Hokiichi HANAWA) are existing today.