The term "Shishi" (also pronounced Shiishi) referred to the northern, southern, eastern, and western boundaries of a tract of territory/land in ancient and medieval times. Later, it became the term that referred to a boundary itself.
When shoen (manor in medieval Japan) was established and officially authorized by obtaining Kugen (official documents authorized by kokushi (provincial governors) or Gunji (local magistrates) for transfer of the ownership of private property), its boundaries with other lands like koryo (public lands) were confirmed in the presence of an envoy dispatched by Imperial court (either Dajokan Benkan kyoku (Oversight Department: division of the Dajokan responsible for controlling central and provincial governmental offices) or Minbusho (Ministry of Popular Affairs)) (kanshi), an envoy dispatched by Kokushi (kokushi) and shokan (an officer governing shoen). Thereafter, they clarified Shishi by putting on Boji (notices) (planting stakes or putting marks on nearby natural things) on the four corners of shoen. The above procedures were called Shiishiboji. In such cases, relevant persons made a picture map (Shiishiboji ezu) that showed the exact position of Boji in order to confirm the territory of shoen and prevent future disputes over its boundaries.