Columbia subject headings:
Harvard subject headings:
Castles--Japan--Inland Sea.
Fortification--Japan--Inland Sea.
Japan--History--Period of civil wars, 1480-1603.
Pirates--Japan--Inland Sea.
Princeton subject headings:
Castles--Japan--Inland Sea.
Fortification--Japan--Inland Sea.
Japan--History--Period of civil wars, 1480-1603.
Pirates--Japan--Inland Sea.