The situation was changed dramatically compared to before, the Choshu Expeditions went fourth, the establishment of the Satsuma-Chochu Alliance, the death of Shogun Iemochi TOKUGAWA, Yoshinobu TOKUGAWA being new Shogun, the death of Emperor Komei and so on, while both Prince Taruhito and Takahito were refrained from making public appearances and had no contact with outside.

The Choshu clan toppled to become chouteki (朝敵), but after the death of Emperor Komei, who belonged to the sect that sought the expulsion of foreigners, Satsuma and Choshu concluded the Saccho Coalition (薩長同盟), and the fifteenth shogun, Yoshinobu TOKUGAWA, seeking the establishment of the Kougi government, conducted the restoration of imperial rule; however, the Meiji Government was established through the acceptance of restoration of imperial rule (Japan), and upon the defeat of the former Bakufu army in the Battle of Toba Fushimi, the order to hunt down Yoshinobu TOKUGAWA was released, and even though the Bakufu structure was legally extinguished, the Tobaku movement through military power became active.

The power thus strengthened was utilized in the Tobaku movement that followed, and while the Satsuma clan pretended to be pro-Bakufu at all times it ended up secretly concluding the Saccho Coalition.

Saccho Domei (Satsuma-Choshu Alliance)

Saccho Domei' refers to the political and military alliance concluded on March 7, 1866 in the last days of the Edo period between the Satsuma Domain and Choshu Domain.

Although this was followed by the offensive carried out by the Shogunate on the Choshu clan, which was deemed the enemy of the Imperial Court, once Emperor Komei died, the Choshu clan was forgiven, and a Saccho alliance was secretly formed between the Choshu clan and the Satsuma clan, which switched its position to bring the end of the Shogunate rule.

Under these circumstances, powerful domains in the western Japan such as Satsuma Domain, Choshu Domain, who repeated political strifes, concluded an alliance (the Satsuma-Chochu Alliance) through the intermediation of Ryoma SAKAMOTO and Shintaro NAKAOKA.

The Satsuma-Choshu Alliance and anti-shogunate movement (1864 – 1866)

After some cooperative work, such as when Satsuma purchased weapons for the Choshu clan, who were officially regarded as a rebels and could not purchase them, both signed the secretive agreement to form an alliance at the Satsuma clan's residence in the presence of Takayoshi KIDO and Saigo in Kyoto in January 1866.

At the very end of the Edo period when the Satsuma clan and Choshu clan formed Satsuma-Choshu Alliance to promote the movement to overthrow the Shogunate, the Tosa clan, which supported the parliamentary regime theory and the Shogun's returning the sovereignty to the Emperor, submitted a petition for Taisei Hokan (proposed and planned by Ryoma SAKAMOTO in cooperation with Shojiro GOTO) to the Shogun Yoshinobu TOKUGAWA through the lord of the domain Toyoshige YAMAUCHI on October 29, 1867.

The Satchodo (Satsuma, Choshu and Tosa Domains) formed a partnership through exchanges held among nationalist patriots from these three domains in the late Edo period, as well as through the Satsuma-Choshu Alliance and the Satsuma-Tosa Alliance.

In 1866 Choshu Domain forged a military alliance (Satsuma-Choshu Alliance) with Satsuma Domain arriving at a consensus on overthrowing the Shogunate, as a result, in January 1868 the Restoration of Imperial Rule came into effect under Saccho's (Satsuma-Choshu Alliance) leadership after Taisei Hokan (transfer of power back to the Emperor) was put into practice in November 1867.

The Satsuma Domain and the Choshu Domain had been in conflict with each other, but an intermediation by Ryoma SAKAMOTO led to the Satsuma-Choshu Alliance.

The army of The Edo Bakufu had been stated as a rebel army in history books for long time, and especially, the leading party of the Bakufu army, the Aizu Domain and the Ouetsu-reppan alliance were treated as the evil personified.

However, because of the Satsuma-Choshu Alliance (Saccho Alliance), Satsuma-han Clan refused to send its army and consequently the Shogunate army had to retreat.

At around that time Ryoma together with NAKAOKA started working on the achievement for Satsuma-Choshu Alliance.

In January, 1866, the meeting between Kogoro KATSURA (Takayoshi KIDO) from Nagatonokuni and Takamori SAIGO from Satsuma was held in Kyoto by Ryoma SAKAMOTO's mediation to achieve Satsuma-Choshu Alliance.

Although Satuma-Choshu Alliance is considered as the Ryoma's major achievement, there is also a theory that Ryoma was in fact instructed by Satsuma clan including SAIGO and Kiyotada KOMATSU to work on the achievement for the Alliance (Tadamasa AOYAMA), and therefore there are divided evaluations over what kind of role Ryoma played for Satsuma-Choshu Alliance.

Starting with the Tadamasa AOYAMA's theory, Satsuma-Choshu Alliance has been a hotly-debated issue among scholars including Norimasa KANBASHI, Tsugunobu MIYAKE, Masato MIYACHI, Hidenao TAKAHASHI and Suguru SASAKI.

For the trend of study on Satsuma-Choshu Alliance, refer to "Reality of the Alliance and The Role Ryoma Played therein" by Sakujin KIRINO ("New Historical Figures Series (4) Creation of the Restoration Ryoma SAKAMOTO" GAKKEN, 2006).