Since the Tang Dynasty, when the country was in chaos due to the strong branches and weak trunk, separatist regimes, and warring states, the principle of strong trunk and weak branches, which had been advocated since the Han Dynasty, has once again become the mainstream since the Song Dynasty. The fact that there were once 800,000 imperial guards stationed in Tokyo during the Song Dynasty originated from this.
Of course, the Song Dynasty not only strengthened the core and weakened the branches in terms of military strength, but also consistently advocated culture over military strength. Even the central government, especially the emperor, would often send out battle formations to command border generals to fight. The Western Army was scattered across many mountaintops, and the imperial guards were rotten to the core.
In the early Ming Dynasty, Zhu Yuanzhang overthrew the Song Dynasty system, divided his sons into vassal kings, and gave them powerful armies as guards, trying to strengthen the borders. As a result, the Jingnan Campaign occurred. The final winner, Zhu Di, took back most of the princes' guards and created three major camps. But the Beijing Camp soon became rotten, and the border troops of the nine borders became the real main force of the Ming army.
The Qing Dynasty was not much better. The Bannermen soon became corrupt after entering the Central Plains. Instead, the Jiangnan Green Camp became the real main force. However, the Green Camp soon collapsed. By the time the Taiping Heavenly Kingdom was in full swing, it relied on forces such as the Hunan Army led by Zeng Guofan himself, the Huai Army led by Li Hongzhang, and the Mongolian soldiers led by Senggelinqin... In any case, most of the time the regular army of the court had a pitiful record.
However, from the Song and Yuan Dynasties to the Ming and Qing Dynasties, the army was not very good, and the navy was also first prosperous and then declining. The navy of the Southern Song Dynasty was once the guarantee of the Southern Song Dynasty's seclusion, but it suffered defeats in the later period; the navy of the Yuan Dynasty gradually grew up in a series of wars, and even went on an expedition to Japan, but later it became rotten; the navy of the Ming Dynasty was no longer good after Zheng He's voyage to the West; as for the Qing Dynasty, look at the Beiyang Navy and the Nanyang Navy...
Therefore, when Zhang Shou arrived in this era, he heard about the early years of Taizu, who divided the country into major command offices and stationed a number of troops there, while at the same time deploying heavy troops on the northern border and vigorously developing the navy on the eastern coast.
However, because the inland areas had always been peaceful and there were few wars, the status and power of the major military commanderies had plummeted within a hundred years, while the importance of the major border towns had never decreased because the northern barbarians often rose up and invaded the border. The navy, which Taizu had high hopes for, was indeed quite good. The navy's ships once covered the sky and the sun, and when they visited the West, they shocked all countries.
Zhang Shou used to think that the Western Ocean mentioned by people today and the Western Ocean mentioned by Zheng He in his voyage to the West were the same, but he later realized that the South Sea was Southeast Asia, the Western Ocean was Europe, and even included India in South Asia. Only the Eastern Ocean... because of Emperor Taizu's obsession, could not be used to refer to Japan. He even thought that the two words Taizu were more likely to refer to the American continent in the East Sea.
Because the two large-scale fleets were invincible when they sailed to the Western Ocean, they terrified everyone who saw them. They encountered pirates twice. Once, the artillery demonstrated firepower suppression at close range, and once, the commander got too excited and had a boarding battle. As a result, merchant ships flying the Ming dragon flag were mostly unimpeded in various parts of Europe. Therefore, the dozens of ships that sailed to the Western Ocean in a show of force gradually disappeared.
Although the navy no longer travels to other countries in a blanket manner, it has been updating its ships. In the early years of Emperor Taizu, ports and shipyards were built in Tianjin, Ningbo, Fuzhou, and Guangzhou. Now, these four places have the most complete fleet and navy in the entire Ming Dynasty. As for the purpose of maintaining such a navy, the main responsibility is probably to investigate smuggling ships that go out to sea without customs permits.