Unauthorized Exchanges: Restrictions on Foreign Trade and Intermarriage in the Tang and Northern Song Empires

This essay reexamines late Tang and Northern Song laws that appear to prohibit private trade, communication, and intermarriage with foreigners, and concludes that they were rooted in early Tang policies rather than an increase in anti-foreign or proto-nationalist sentiment. It also argues that in the Northern Song, restrictions on foreign trade and intermarriage gave way to more liberal or targeted approaches, the main exceptions being strategic restrictions on trade along the northern borders and maritime trade with Đại Việt and Koryŏ. When the Song state implemented or contemplated restrictions on intermarriage in certain frontier locations, this was typically for strategic reasons of counterintelligence, not xenophobia or ethnic segregation.