Columbia subject headings:
Harvard subject headings:
Fortification--Japan--History.
Fortification--Korea--History.
Japan--Relations--Korea.
Korea--History--Chosŏn dynasty, 1392-1910.
Korea--Relations--Japan.
Princeton subject headings:
Fortification--Japan--History.
Fortification--Korea--History.
Japan--Relations--Korea.
Korea--History--Chosŏn dynasty, 1392-1910.
Korea--Relations--Japan.