What changes have taken place in China's foreign trade since the Tang Dynasty?

After the Tang Dynasty, China's foreign trade mainly changed from land trade to maritime trade, and then from maritime trade to maritime prohibition.

The Silk Road in Han Dynasty opened the development of China's foreign trade. Before Sui and Tang Dynasties, China's foreign trade was mainly based on the Silk Road, and the main trading countries were also the countries around the Silk Road. After Sui and Tang Dynasties, land trade became more and more difficult because of the blockage of land trade channels by ethnic minorities. Coupled with the improvement of shipbuilding technology and navigation technology at that time, people gradually turned their attention to foreign trade to maritime trade. The Tang government also set up the Municipal Shipping Department to supervise the waterway trade. Due to the obstruction of ethnic minorities, the Tang dynasty began to strengthen the supervision of the mutual market, but began to increase support for maritime trade, encourage and open maritime trade.

During the Song and Yuan Dynasties, maritime trade developed further. The rulers of Song and Yuan Dynasties hoped to obtain more overseas treasures through maritime trade, actively encouraged maritime trade, exempted official trade in the name of "tribute", set up foreign trade officers in Guangzhou, Hangzhou, Quanzhou and Wenzhou, and customized the "Urban Maritime Law" to strengthen the management of maritime trade.

During the Ming and Qing Dynasties, Emperor Hongwu began to implement the policy of sea ban in order to maintain feudal rule and prevent Japanese invasion. In the first year of Hongwu, the law clearly stipulated that the sea people were not allowed to go out to sea privately, and were not allowed to engage in maritime trade such as gold, silver, steel, silks and satins, weapons, etc., and only official "tribute" trade was allowed. The long-term sea ban has not blocked all overseas trade, and more people choose smuggling trade. The emergence of smuggling trade has further led to social chaos and piracy in the local coastal areas. During this period, it was not that no monarch wanted to abolish the sea ban, but he did not succeed. So China's overseas trade developed into a maritime ban, which also hindered the budding development of capitalism in China.