Naohide ran to the port early in the morning and didn't relax until he got on the ship, and the owner of the ship was also on board, he was a merchant of the Saga Nabeshima family, and he usually ran the route "Nagasaki-Shimonoseki-Osaka" to sell goods. The owner of the boat is quite talkative, and Naohide has nothing to do at sea, so he talks to the owner of the ship about the scenery and gives the two students a long insight.

In 1603, when the Tokugawa shogunate was first established, in order to import goods in urgent need of goods and clean up the mess left by the failure of the Toyotomi administration's expansion policy, Fuso's trade with China, Goryeo, Southeast Asia, and Western countries flourished.

The shogunate practiced concession trade, and granted concessions to the owners of merchant ships that traveled between foreign countries and Fuso, and the franchised merchant ships were known as "Goshu-seals", and the owners of the ships were mostly daimyo in Kyushu, wealthy merchants from all over the world, shogunate officials, and foreign merchants. The main products exported were gold, silver, copper, sulfur, camphor, rice, Japanese swords, lacquerware, and fans, and other exquisite handicrafts, and the main imports were silk, saltpeter, woolen wool, sumac, deerskin, dyes, spices, lead, tin, sugar, medicinal herbs, Korean ginseng, etc., which had a great impact on the economy of Fuso at that time. At that time, Fuso was inferior to foreign countries in terms of shipbuilding and navigation technology, so it was inconvenient to engage in entrepot trade, but Fuso was rich in gold, silver, copper and other precious metals, so the import and export trade was very prosperous.

One of the more special ones was the trade between China and Fuso at that time, because the "Wanli War to Aid Goryeo", one of the three major expeditions of the Ming Dynasty, (called the "Imjin War" by Goryeo and the "Battle of Wenlu Keichancho" by Fuso), had just ended, and the Ming Dynasty rejected the shogunate's request for trade. After the negotiation failed, the shogunate tried to negotiate with the help of the Ming vassal states such as Ryukyu and Goryeo: in June of the 11th year of Keicho (1606), the shogunate learned that the Ming envoy had arrived in Ryukyu and asked the Ming envoy to "restore the Ming Dynasty and Fuso merchants, the existence of currency and wealth", and "from now on, Futong financial bribes", but the Ming court replied that it was strictly forbidden for Ryukyu to contact the "Japanese people". Similarly, due to the haze of war, Goryeo refused to pay tribute on the grounds that "in ancient times, Ann had borrowed the road from the neighboring countries, wore through the belly, and reached as far as other countries". Fuso's attempts to mediate between the two countries also failed, and the shogunate tried again but was never allowed. As a result, the shogunate gradually abandoned the official demand for cooperation in favor of resuming private trade between the two countries.

In the face of the enthusiastic attitude of Fusang, businessmen from Fujian, Guangdong, and Zhejiang provinces responded positively, and the number of Chinese Fusang people in Fusang increased year by year. In August of the sixteenth year of Qingchang (1611), "more than 80 merchant ships from the foreign land of the Southern Barbarians of the Ming Dynasty came to the DPRK", and in July of the following year, there were "26 merchant ships of the Ming Dynasty and Luzon returning ships", carrying more than 200,000 catties of raw silk. By June of the 19th year of Keicho (1614), there were 70 ships in Nagasaki that year. "If the survey failed, the number of merchants from Nanjing and Fujian who crossed Nagasaki every year has increased year by year", and the once-interrupted private trade has resumed. Therefore, although the Ming Dynasty was not reopened, the shogunate's change from restarting the official survey to encouraging private merchant ships to sail made Fuso resume trade with the Ming Dynasty.

As for Goryeo, in order to bring back the Goryeo people who had been taken captive during the Imjin War, they agreed to trade with Fuso after several negotiations, and from the 12th year of Gyeongcho (1607) to the 8th year of Bunka (1811), Goryeo sent 12 Goryeo envoys to Fuso for trade, the first 11 of which reached Edo, and the last one was on Tsushima Island. Because the diplomatic activities in the form of diplomatic envoys in the form of Goryeo communication were very costly, and the financial resources of the two countries could not support it, so they automatically stopped, and the private trade continued between Fuso Tsushima Island and Goryeo Busan.

With the recovery of the Fuso economy, foreign trade brought unexpected problems at the time.

First of all, the proselytizing of Western merchants and Kiritan priests led to the insecurity of the shogunate, and various conflicts occurred between the Kiritan missionaries and religious people and the traditional samurai ruling class and local Buddhism, and even foreign merchants secretly reported to the shogun that the Kirchitan missionaries intended to be unfavorable to the shogunate.

Second, foreign trade led to a large outflow of precious metals such as gold, silver, and copper from Fuso, and domestic commodity prices skyrocketed, triggering civil unrest.

The shogunate then discovered that the daimyo of Kyushu were growing rapidly through foreign trade, while the shogunate had relatively little to gain.

As a result, the shogunate's attitude towards foreign trade changed.

In 1616, the shogunate decreed that foreign ships (except those of the Ming Kingdom) would be prohibited from berthing outside the ports of Hirado and Nagasaki. In the 6th year of Motowa (1620), the Fuso people were forbidden to board foreign ships and the export of weapons was prohibited. In the 8th year of Motowa (1622), the shogunate massacred foreign and native Chechi priests, and the following year expelled all the Portuguese from the country. In the first year of Kanei (1624), ships from the Nanban (Spain and Portugal) were forbidden to enter the country.

In the 10th year of Kanei (1633) and the 11th year (1634), the shogunate issued the first and second lockdown decrees, implementing the "Fushu ship" system, stipulating that Fuso people and Fuso ships were strictly prohibited from leaving Fuso, except for ships with concession certificates. The "Fengshu Boat" system means that in addition to the seal, the ship going to sea must also have a document issued by Laozhong, and at that time, only licensed merchants could obtain this kind of license document. At the same time, foreign trade was strictly restricted, foreign ships coming to Fuso were monitored, trading within a limited period of time, leaving the country when due, the price of raw silk was regulated by Nagasaki (other commodities were priced according to the standard of raw silk), officials were forbidden to buy foreign goods directly, and the arrest of Nanban priests was strictly ordered, and rewards for those who denounced the priesthood were promulgated. As a result, the shogunate trade was monopolized by seven shogunate-chartered merchants, including Kakukura, Chaya (Kyoto), Sueyoshi (Osaka), and Miura Shoring, and the raw silk trade was monopolized by merchants from Kai, Nagasaki, Kyoto, Edo, and Osaka.

In the 12th year of Kansui (1635), the third lockdown decree was issued, prohibiting all Fuso ships, including charter ships, from sailing to foreign countries, and Fuso people who went to foreign countries were to be executed without asking for reasons after returning to Fuso.

In 1636, the 13th year of Kansui (1636) issued the Fourth Decree on the Closure of the Country, which, in addition to the first ban, added a decree to the death of all children born to Nanban in Nagasaki and those who took in or rescued these mixed-race children, and strengthened the search for foreign priests. In this way, the trade blockade, which had been strengthened with the ban on religion, was gradually tightened.

In the 14th year of Kanei (1637), the "Shimabara Rebellion" ("Amakusa Rebellion") broke out, and the peasants who revolted rebelled against the harsh government and atrocities of the lord with the people as the core, repelled the first, second, and third attacks of the shogunate coalition according to the castle defense, and killed the raider Itakura Shigemasa sent by the shogunate on the spot.

This incident was a great shock to the shogunate, the daimyo and the Fuso society at the time, the Shimabara Matsukura family was confiscated of the territory, the head of the family Matsukura Katsuya was sentenced to beheading, becoming the only person in the Edo period daimyo to be beheaded (cutting the belly is not beheaded), the Amakusa Tera Sawa family was confiscated territory, the head of the family Terasawa Kentaka committed suicide due to mental disorders, and the Terazawa family has been cut off since then. So far, the two daimyo who caused the Shimabara War have been destroyed.

In 1639, the shogunate issued its fifth and final edict to ban foreign ships from Fuso, order the princes to inspect the ships, triple the bonuses for smuggling foreign ships, and prohibit all Western churches from having contact with the people of Fuso.

In the 18th year of Kanei (1641), all the Lan people were transferred to the artificial island of Nagasaki "Dejima", and a list of forbidden books was established to restrict the import of foreign language books, and even the trade of vermilion ships was banned. With the exception of the Goryeo Fuso trade in Tsushima, the shogunate allowed ships from China and Lan to sail only to the port of Nagasaki, because Nagasaki was the Shogunate's Heavenly Domain, so the shogunate controlled the trade between China and Lan, and the raw silk trade, the most important commodity in the trade, was monopolized by the wealthy merchant group "Silk Cutting Fu Nakama", which held the shogunate's raw silk concessions.

From this point on, the shogunate's policy of closing the country was basically completed.

In order to cooperate with the policy of seclusion, the shogunate implemented a system of "temple invitation" or "unauthorized family", in which each Fuso person had to choose a temple as his own "temple", and the temple would prove that he was a follower of a certain Buddhist sect. Since then, Buddhism has flourished.

Since then, Nagasaki has been the only international trading port in Fuso at that time, and has become the most prosperous commercial city outside of the three capitals, receiving Lan and Chinese merchants.

Influenced by Choshu Shiraishi Shoichiro's careful reception of him, Naohide only roughly talked about ancient things with the shipowner and merchant, did not explain the situation mentioned above, and also instructed the merchant and the two students to "I have not understood it thoroughly, but only talk in private, and do not spread it so as not to laugh at it."

Four days later, the ship sailed into the port of Nagasaki, and Naohide bid farewell to the owner with nine Kanei judgments.

In fact, in addition to the route from Nagasaki by sea, Naohide considered going from Shimonoseki to Kokura via the Shimonoseki Strait, and then to Nagasaki via Saga Castle, so that he could visit his teacher Ito Genpo first, which seemed to be closer. But now it is not allowed to use horse-drawn carts, ox carts and large eight carts only pull goods, and the speed of walking by land is relatively slow, although the Ogura Ogasawara family is a pedigree dai daimyo and is more friendly to the shogunate, but in case of running into that crazy samurai to make trouble for himself, think about it, although the boat ride is a little more expensive, but it is much more comfortable.

Nagasaki was the second city in the world to be destroyed by an atomic bomb after Hiroshima. But then Nagasaki developed and ranked in the top 150 of the world's top 500 cities, which is inseparable from its convenient transportation location.

Nagasaki is located at the western end of the Nagasaki Peninsula in the western part of Kyushu Island, surrounded by mountains on three sides, facing the sea on one side, the port is 159 nautical miles south of Kagoshima Port, about 40 nautical miles northwest of Sasebo, and only 448 nautical miles west of Chugoku Wusong Port. The port is located in the Nagasaki Sound, there are Kayakaki Island, Yiwang Island and other harbors outside to protect the wind and waves, the tide rise in the bay is 2.1-2.9 meters, the average sea surface wave is 1.64 meters, the outer section of the incoming channel is 2.1 kilometers long, 460 meters wide, and the water depth is 38-45 meters, the middle section is 1.84 kilometers, the width is 200-330 meters, the water depth is 27-40 meters, and the inner section is 1.43 kilometers long, 180 meters wide, and the water depth is 18-24 meters.

All in all, Nagasaki is a natural shelter and is well located for international trade.