Columbia subject headings:
Harvard subject headings:
Investments, Japanese--Government policy--East Asia--History.
Narcotic laws--East Asia--History.
Opium trade--Government policy--China--History.
Opium trade--Government policy--East Asia--History.
Princeton subject headings:
Investments, Japanese--Government policy--East Asia--History.
Narcotic laws--East Asia--History.
Opium trade--Government policy--China--History.
Opium trade--Government policy--East Asia--History.