During the Edo period, several powerful feudal clans in the southwest were already very strong, but at that time, the shogunate was still able to cover it, and finally there was no trouble. However, with the Black Ship Knock Incident, all the situation changed, and the samurai, who decided the direction of the country, were divided into the Zun faction, which respected the king, and the founding faction, which sought to learn from the West.

The Enlightenment faction is a minority of the minority, so small that it is almost negligible, so the focus is on the Zun faction. Although the two factions are also under the banner of respecting the king, the two factions have fundamentally parted ways, not only can they not work together, but they have to be pinched to death when they meet.

Originally, the vast majority of people, including Nagasu and Satsuma, supported the combination of public and military forces, but as the shogunate dropped the chain again and again, more and more people were completely disappointed in the shogunate and turned into the shogunate faction. In order to make the country develop in the direction they expected, the Gongmu faction and the Shogunate faction were endlessly tossed several times at the end of the Edo period, and the August 18 coup d'état, the Forbidden Gate Rebellion, and the Kozanji Uprising were almost turned into a battlefield by Kyoto, where the emperor lived. The emperor's house is about to be demolished, and it is really a bit unreasonable, and some people of insight also feel that such a blind toss is not a way at all, and the representative figure is Sakamoto Ryoma.

Sakamoto Ryoma's real name was Naoyu, and his humble background was that his grandfather, Naoyi, was originally a young proprietor of the hotel "Saiya House", and later succeeded to a low-ranking samurai family in the Tosa Domain, and only then did he obtain the qualification of "country warrior". Ryoma once left the feudal domain and went to Edo with the intention of assassinating Katsukaishu, the shogunate of the founding faction, but was persuaded by Katsukaishu and became one of the main advocates of the founding theory.

Ryoma Sakamoto conceived his own unique republican form of government, and he later founded the Kameyama Shochu in Kameyama, Nagasaki, which later became known as the Sea Aid Force. The Kameyama Society was not only a business and trade organization, but also a general liaison and information station for the king's aspirants, and through this organization, Ryoma devoted a lot of energy and money to the movement to bring down the king.

Sakamoto Ryoma was not in favor of the overthrow of the shogunate by force, believing that only by uniting the feudal domains could the shogunate be forced to automatically "return the great government", that is, to return power to the emperor's court and complete a bloodless revolution. To accomplish this, Ryoma decided to first bring together the two largest bases of the Zunzao faction, Choshu and Satsuma.

The Satsuma Domain and the Nagasu Domain were not very harmonious, whether it was the August 18 coup, the Forbidden Gate Change, or the shogunate's first crusade against Nagasu, the Satsuma Domain made great efforts. The people of Changzhou hate the most about rape and thieves, and in their eyes, the Satsuma Domain and the Aizu Domain are the same bastards. Only a person as bold and courageous as Ryoma Sakamoto dared to lobby for the union of the two feudatories, and it was impossible to think about it if he changed ordinary people.

When Ryoma Sakamoto and his friend Shintaro Nakaoka came to the Satsuma Domain, the real power in the domain was held by Saigo Takamori and Okubo Ritsu, the general staff of the First Choshu Expedition. The Satsuma Domain's former association was to assist the shogunate in the war with the Choshu Army, in order to seize real power in Kyoto and fulfill the political ideals of the feudal lord Shimazu Hisamitsu and the "Tsuyo Domain". However, after the defeat of Choshu, the shogunate unloaded the mill and killed the donkey, accelerated the restoration of the shogunate's power, and deliberately stirred up the Xiongvan meeting convened by Huang Mingling. Under these circumstances, the minds of Saigo Takamori, Okubo Ritsu, and others began to lean toward the fall of the curtain by force. After repeated persuasion by Ryoma and Shintaro, Saigo Takamori finally agreed to join forces with Choshu and wait for an opportunity to overthrow the corrupt rule of the shogunate. Then, the two came to Choshu to lobby, although the people of Choshu hated the "rape" and "thief", but the broad-minded Katsura Kogoro and Takasugi Shinsaku still tried their best to overcome public opinion and decided to strive for Satsuma, a strong foreign aid.

Under the repeated lobbying of Ryoma Sakamoto and Shintaro Nakaoka, in the first month of the second year of Keio, Choshu Minister Katsura Kogoro secretly infiltrated Kyoto again, met with Saigo Takamori at the Satsuma Domain, and signed an alliance agreement to advance and retreat together. The shogunate was ignorant of this secret alliance, and they only saw Takasugi Shinsaku's "Kozanji Rebellion" and the Choshu Domain's tendency to secession, so they decided to launch the second "Seicho War".

Although the Satsuma Domain stopped playing this time, General Ieshige still cobbled together 150,000 troops from each feudal alliance and surrounded the Nagaga Domain from four directions: San'in, Sanyo, Seto Inland Sea, and Kitakyushu. The Shogunate's vanguard commander was Tokugawa Shigeruni, and Ieshige personally left Edo to command the battle from Osaka Castle. The shogunate's 30,000 army troops took the Ishukou Pass from the direction of San'in, the 50,000 army troops from the direction of Sanyo took the Eju Pass, the 20,000 land and water forces landed from the south of Nagato and took the Oshimaguchi Pass, and the main force of 50,000 troops took the Kyushu Pass as a base based on Kokura Castle in northern Kyushu, aiming directly at the important town of Shimonoseki in Choshu and the main city of Hagi Castle. Compared with the shogunate's 150,000 troops, Choshu's battleable soldiers were only 4,000. If General Ieshige can level the Nagasu Domain this time, the course of Japanese history will definitely be completely rewritten, but unfortunately the Nagasu Domain has an unborn genius - Masajiro Omura.

The War of the Four Frontiers lasted less than two months, and the curtain came to a hasty end because of the death of General Jiamao due to athlete's foot, and from any point of view, it was won by the Cheung Chau Domain with 4 kilograms and 150,000 yuan. The war completely destroyed the authority of the shogunate, causing the prestige of the shogun to plummet, and the Chosu domain officially became a secession domain that was not under the control of the shogunate.

The reason why Choshu was able to win the "Four Frontiers War" was due to many reasons, the most important of which was the decay of the shogunate and the poor equipment and coordination of the allied forces of the feudal domains, while Choshu was well-equipped after the reform of the military system, and at the same time, the morale of the whole army was high. In addition, Satsuma and the British covert support for Choshu also played a big role.

At that time, Britain and France were vying for control of Japan, and the British believed that the shogunate was too corrupt to use it to rule all of Japan, so they turned to the Satsuma and Choshu feudal domains, which were gradually opening up their borders, in the hope of realizing a system of alliance of feudal domains centered on the emperor, which was envisioned by Sakamoto Ryoma. Seeing this British attitude, France strengthened its support for the shogunate. It can be said that if the British had not been involved, Choshu might not have been able to easily win the "Four Frontiers War", and if the French did not stir up trouble in it, it is likely that Takasugi Shinsaku would have taken advantage of the victory to pursue and take Kyoto directly after the victory.

With the death of the 14th shogun, Tokugawa Ieshige and Emperor Takamei, the last shred of hope for the Gongmu alliance was extinguished, and the curtain fell into the most important event in Japan.