In the 1430s, what policy did china follow in terms ofcontact with other countries?

China during the 1430s was the time of maritime explorations. The main reason for doing so is to trade with other countries. Zhu Di ordered for a great maritime explorations and left together with the fleet. The explorations were put on halt due to his death. The next emperor saw it as unnecessary and made a policy of Maritime Ban. Due to this policy the country was not able to trade and establish relationships with outside. The policy was lifted a few years after to regain trade functions but was later implemented again.