one country, two systems
Refers specifically to the Chinese policy principle applied to Hong Kong and Macau. The more common Japanese term is 一国二制度 (いっこくにせいど).
See also: 一国二制度
One country, two systems is China's basic policy toward Hong Kong and Macau.
More common Japanese term for the same concept; 一国両制 is a less frequent variant.
From Chinese 一國兩制 / 一国两制 (yī guó liǎng zhì), literally 'one country, two systems'.