Columbia subject headings:
Harvard subject headings:
Forced labor--Japan--Hokkaido--History.
Foreign workers, Korean--Japan--Hokkaido--History.
Service, Compulsory non-military--Japan.
World War, 1939-1945--Conscript labor--Japan.
Princeton subject headings:
Coal mines and mining--Japan--Hokkaido--History--20th century.
Forced labor--Japan--Hokkaido--History--20th century.
Foreign workers, Korean--Japan--Hokkaido--History--20th century.
Service, Compulsory non-military--Japan--Hokkaido.
World War, 1939-1945--Conscript labor--Japan--Hokkaido.