The ruler of the old Japan was the Tokugawa shogunate, whose ruling center was in Edo Castle, and after the "royal government", the emperor was still the nominal leader, and the new government centered on the southwestern feudal lords such as Sa, Naga, To, and Hi was established in Kyoto, and then the new government waved its army to the east, and Keio entered Edo in March of the fourth year, so it can be said that the struggle between the old and new forces has been settled at this point, and the war should be over.

But Japan is not a centralized country, and the shogun still has a large number of younger brothers in the Kanto region! The princes in the east could tolerate the emergence of a new government, but they could not tolerate the new government being in the hands of the southwestern feudal lords, and they demanded their own place. If those people with lofty ideals really served the country and the people and had no selfish intentions, this problem would have been easily solved. It's a pity not to mention arranging places for outsiders like them, the interior of the new government is crowded enough. There were many contradictions between Sa and Naga, Okubo Ritsu and Saigo Takamori always wanted to seize the real power in the hands of the Sa Domain, and focused on squeezing out and suppressing the Nagaga Domain, while Omura Masajiro of the Nagaga Domain commanded the battle several times, all of which were led by the Satsuma soldiers, ostensibly "good steel should be used on the blade", but in fact they wanted to use the lives of the Satsuma people to pave the way for the Choshu administration. As soon as the new government was formed, its own people began to compete for power and profit, so how could it be possible to allow outsiders to get a piece of the pie?

"We are loyal to the king, and we do not hesitate to shed blood, and you Eastern Domain have always been the lackeys of the shogunate, but now you want to become a member of the new government, how can there be such a good thing in the world that benefits without expense?" Seeing through the thoughts of the east, the southwest feudal lords all scolded their mothers in their hearts.

In May of the fourth year of Keio, Date Keibang, the lord of the Sendai domain, and Uesugi Saiken, the lord of the Yonezawa domain, proposed to the new government, Kujo Michitaka, the governor of the Okuwa Shofu, that they want to be lenient with the Aizu domain. Aizu is a pro-domain of the shogunate, and the ancestor of the domain, Hoshina Masayuko, was the fourth son of Tokugawa Hidetada, and passed on to the spectrum of Hoshina Masamitsu, inheriting the Miao character of Hoshina, and the Hoshina clan was first sealed in Shinano Takato, then moved out of Hayamagatata, and finally changed to the wealthy Mutsu Aizu, and restored the Miao character of the main family Matsudaira. Matsudaira Yoho, the lord of the Aizu domain, was the vanguard of the Samu, and all the people who respected the lofty ideals hated him, and they had to get rid of it as soon as possible.

In fact, Sendai and Yonezawa have a general relationship with Matsudaira Rongho, and there is no reason for the Matsudaira clan to stand out. They just wanted to observe the attitude of the new government and see how it would deal with the northeastern domains. As a result, Kujo Michitaka brazenly rejected the request of the two families, and on June 22, the "Ou Alliance" was formed, led by the Aizu Matsudaira clan and the Sakai clan of Dewa Shonai, to jointly resist the northward advance of the new government forces. Later, the Hokko-Go-Nagaoka and Shinbata feudal clans also joined one after another, and it was the "Ou-Etsu Domain Alliance", with a total of 31 princes. The Nagaoka Domain, after North Vietnam, joined the alliance very late, but its performance was very eye-catching, because they were wronged!

After sweeping away the stumbling blocks around Edo, Masajiro Omura began to sweep through the Kanto region, only to find the new government forces in the Hokuriku region. On April 27 of that year, the Hokuriku Front, a new government army, occupied Kochiya in central and western Echigo, and ordered the nearby princes to quickly express their support for the new government or the Tokugawa clan, the "enemy of the dynasty."

When the news reached the Nagaoka Makino Domain, the shogunate of 70,000 koku, the old Kawai Kenosuke convened his retainers to discuss countermeasures, and some of the retainers leaned towards the new government, while others leaned towards the old shogunate, and attacked each other endlessly. Eventually, Kawai Keinosuke finalized the policy of "armed neutrality" and personally went to Kochiya to negotiate with the new government forces.

Kawai Jinosuke hoped that the new government army would temporarily bypass the Nagaoka domain and advance eastward bypassing the Nagaoka domain in consideration of the contradictory situation of public opinion in the Nagaoka domain, but this request was rejected by the new government military superintendent Iwamura Seiichiro. "The Tokugawa clan has shown their respect, and Edo Castle has opened its gates, and today war is no longer necessary. If there is a war, it will only lead to the destruction of lives and the weakness of the country, and the Western powers will take advantage of the weakness. Why can't your army take a detour for the time being, while the internal discussion of countermeasures continues? ”

What Jinosuke said is very reasonable, but from the perspective of the new government army, it is impossible to rashly advance eastward without the Nagaoka Domain's back, which is tantamount to planting a * behind one's back. Eventually, the negotiations broke down, and a frustrated Kawai returned to Nagaoka and immediately prepared for a fierce battle with the new government forces.

However, a small place of 70,000 koku in Nagaoka, although it has been operated by Kawai for many years, and the army is strong, it will not be able to compete with the new government army after all. As a result, Jinosuke joined the "Oku, Yu, and Etsu Domain Alliance" formed by the former shogunate and geneashi in the Hokuriku and Tohoku regions, seeking reinforcements and jointly resisting the enemy.

The main commander of the Allied forces in the Hokuriku region was Kawai Jinosuke, and the actual commander of the new government army was the staff officer of the Hokuriku Province Governor's Office and Choshu Shigetomiyama Prefecture Kurosuke. The two sides first exchanged fire on the Shinano River on May 10, and in the first round, the new government army suffered a major defeat due to the retreat of the Owari feudal army, and then the Choshu army led by Yamaguchi Kusuke launched a full-scale counteroffensive on the 11th, occupying the commanding heights of Asahi Mountain, and reversing the defeat. In the early morning of the 13th, the Allied forces launched a fierce attack on Asahi Mountain, and the new government forces were defeated and retreated. On the 19th, Yamaguchi led his army to make a surprise attack and capture Nagaoka Castle, dealing a heavy psychological blow to the Allied army.

By June, reinforcements from the allied princes of Austria, Yu, and Vietnam had arrived at the front line, and the new government's East China Sea troops, which had solved the problem of Ueno's "Changyi team," were also reinforcing northward. On July 27, Kawai took advantage of his familiarity with the nearby geography to send troops to attack Nagaoka and recapture the castle. However, just as he wanted to take advantage of the victory to pursue and completely defeat the new government army, he found that the Satsuma army, which was famous for its combat effectiveness, had come to the aid in large numbers, and had already forced down the Shinbata Mizoguchi domain west of Nagaoka.

During a fierce battle with the Satsuma army, Kawai was shot in the leg and forced to retreat from the battlefield. The Allied Army, which had lost its commander, fell apart, and each domain was either broken or forced to surrender by the new government forces, and on the 29th, the new government forces captured Nagaoka Castle for the second time, announcing the end of the "North Vietnam War".

When Yama Prefecture Kansuke attacked and occupied Nagaoka Castle for the first time, Kawai Jinosuke asked for help from the Shinbata and other clans, but Mizoguchi Naomasa, the lord of the Shinbata domain, was stopped by hundreds of peasants in his domain on the day of his battle. These peasants, led by Ogawa Gobei, the landlord of the Great Shoya (landlord), armed with wooden sticks and bamboo guns, stopped in front of the city gate and shouted: "You must not be enemies with the official army, otherwise you will surely perish!" Mizoguchi Naomasa had no choice but to retreat into the city, and then he secretly communicated with Yamaguchi Kusuke and surrendered to the new government army.

With the first one, there was the second, and the members of the Ou Domain Alliance rebelled one after another, and the defection of the Miharu Domain directly burned the war to the territory of Nihonmatsu, so that Asano Munehide's relatives had to go to the battlefield.