The opening-up of China and France can be roughly divided into three steps: reporting to China, defending disciplines and changing markets. In the Ming Dynasty, merchants were encouraged to transport grain to the frontier fortress in exchange for the introduction of salt, and the salt selling system was granted a patent. Also known as Kaifa method. The system of opening middle schools followed the system of Song and Yuan Dynasties, but in the Ming Dynasty, more middle schools were opened in border areas to attract businessmen to transport grain to border areas and enrich the military grain reserves in border areas. In the fourth year of Hongwu (137 1), the Zhongyan case was formulated. According to the mileage, one to five stones of grain can be exchanged for a small amount of salt (200 kg) from the government. This situation will change with the situation and the price of rice. In newspapers, salt merchants transported grain to designated granaries in border areas according to the requirements of the investment list of the Ming government in exchange for the introduction of salt by the government; Keeping the system means that after salt merchants exchange salt for salt introduction, they wait for salt assistance at the designated salt field with salt introduction; This market is convenient for salt merchants to transport the salt they get to designated areas for sale. Because of the huge cost of long-distance transportation of grain, salt merchants used to hire laborers to open up wasteland on all sides to produce grain and put it in storage on the spot in exchange for the introduction of salt, thus gaining more profits. Because this form of reclamation is run by businessmen, it is also called Shangtun. In the early Ming Dynasty, Shangtun reached Liaodong in the east, Xuanda in the north, Gansu in the west, and Jiao Jiao in the south. Its prosperity played a certain role in the reserve of military grain for frontier defense and the development of frontier areas. According to the needs of the Ming government, in addition to exchanging grain and rice for salt, sometimes cloth, silk, money, horses, etc. can be exchanged, but the main form is to exchange grain. During the reign of Emperor Xianzong, all parties stopped opening laws and regulations, so that salt merchants received food from the Ministry of Commerce and the Ministry of Transport in exchange for the introduction of salt. At that time, with the increasing corruption of the ruling class, the royal family, eunuchs, nobles and bureaucrats saw that it was profitable to hold salt, and began to discuss the resale of salt to salt merchants for profit. This phenomenon is called "occupying the nest". This phenomenon is getting worse and worse, which undermines the opening-up system and seriously affects the government's fiscal revenue. It is imperative to reform the salt law to make up for the national fiscal revenue. During the reign of Hongzhi in Xiao Zhong, Ye Qi was the minister of finance, and the old system was changed to merchants replacing rice with silver, which was handed over to the Ministry of Communications, delivered to Taicang and distributed to all parties. Every time salt enters, silver loses three or four dollars, resulting in more than one million silver in Taicang, and the national fiscal revenue has soared. Therefore, most of the salt merchants in the border areas moved, and the merchants soon disappeared, greatly reducing the grain reserves of the border guards. During the reign of Emperor Shizong of the Ming Dynasty, Yang Yiqing invited Shang to open a middle school for Shang Tun. Invited by many parties, in the second year (1568), Pang was appointed as the right suggestion, in charge of salt administration and land reclamation, and in charge of nine borders and martial arts. He and Wang Chonggu, governor of Trilateral Shaanxi Province, made a detailed plan to reclaim land in the border areas, but the system was abandoned for a long time and it was difficult to get effective results.
The implementation and influence analysis of the opening-up and economic opening-up in the early Ming Dynasty: As one of the basic economic systems of the Ming Dynasty, China's opening-up and economic opening-up were modeled after the salt law system of the Yuan Dynasty, in order to adapt to the early Ming Dynasty.
The economic policies formulated to prevent the invasion of the remnants of Mongolian and Yuan Dynasties gradually became one of the basic economic policies of the Ming Dynasty, which played a positive role in the social and economic recovery and development in the early Ming Dynasty, especially in defending the border defense. Later, it gradually became one of the basic economic systems of the Ming Dynasty. With the protection of legislation, the policy of popularizing law was better implemented, which almost ran through the whole Ming Dynasty, and also promoted the development of commodity currency economy and the rise of regional commercial groups in the middle of Ming Dynasty.