Kobu Gattai (Alliance between Imperial Court and Shogunate) (公武合体)

Kobu gattai is a policy promoted in the second half of the Edo period which aimed to reassert the power of the Shogunate by bonding the traditional authority of the Imperial Court to the Shogunate. It is also known as Kobu gattai theory, Kobu gattai Movement, and Kobuichiwa.

The Shogunate aimed to re-strengthen its power and to involve the major clans in government by associating itself with the traditional authority of the Imperial Court, and to suppress the Sonno joi or Sonno (Revere the Emperor, Expel the Barbarians) Movement and strengthen and reorganize the structure of the Shogunate.

Under the Shogunate system during the Edo Period, the political power of the Imperial Court was restricted and it was confined to the management of the Court. On the other hand, it ranked at the top of the religious and ceremonial hierarchy and maintained traditional authority. In the second half of the Edo period, the authority of the Shogunate became shaky, affected by famine in the countryside, riots in the cities and the visits of foreign ships to Ezo district and Nagasaki. Around the time of Emperor Kokaku, the Imperial Court tried to regain its authority, and negotiations, such as the Songo Case (an effort by the emperor to give an honorary title), were conducted with the Shogunate.

Commodore Matthew Perry of the United States arrived in Japan with a presidential message in 1853 and demanded the establishment of a trade relationship. Some in the Shogunate had the view that they should acquire Imperial permission from the Imperial Court in order to sign a treaty with a foreign country, and a decision was made to seek the judgment of the Imperial Court on whether to maintain the sakoku policy (seclusion) or an open-door policy.

Naosuke II was appointed Tairo (Chief Minister) in the Shogunate and drove policies against the wishes of the Imperial Court, such as signing the Japan-US Treaty of Amity and Commerce and arbitrarily naming Yoshitomi TOKUGAWA (Iemochi TOKUGAWA) of the Kii Domain as the next shogun. Emperor Komei, who wished for Kobu gattai, issued an unofficial Secret Order of Bogo (Bogo was the zodiac of the year) to the Gosanke (Three Tokugawa Families just below the house of Shogun) and Gosankyo (Three Tokugawa branches besides Gosanke). To countermand this move, Ii suppressed the supporters of the Sonjo such as the Hitotsubashi Group by carrying out the Ansei Purge, which led to the Sakuradamon Incident in 1860 when Ii was assassinated.

The Mito School, which was at the heart of the Sonnojoi Movement, held a belief that the authority of the Imperial Court should suppress the rise of autocratic Shogunate. Once Ii was assassinated, the Sonjo Movement led by the lower ranking warriors from various clans became more violent. In Kyoto, clans from the southwest region, such as Choshu and Satsuma, involved themselves in national politics by making contacts with court nobles. Hisamitsu SHIMAZU, the most powerful man of the Satsuma clan, led forces to Kyoto, suppressed the Sonnojoi group and promoted Kobu gattai by influencing the Imperial Court. Hisamitsu toured to Edo with the Imperial Envoy, Shigetoku OOHARA, and demanded that the Shogunate accept Keiki HITOTSUBASHI (Keiki TOKUGAWA) as the successor Shogun and reform the Shogunate.

In 1861, he succeeded in having the sister of Emperor Komei, Princess Kazunomiya, become the wife of the 14th Shogun, Iemochi TOKUGAWA, on condition that the Shogunate eliminate contact with foreigners. However, the effects of the arrangement were lost once Iemochi TOKUGAWA and Emperor Komei died, and the Sonjo group became dominant in Kyoto and led others in demanding that the Shogunate eliminate contact with foreigners.

Keiki HITOTSUBASHI, representing the Shogunate, went to Kyoto to have the Entrustment of Political Power confirmed but the Sonjo Group aimed for the restoration of imperial rule by having the Emperor tour throughout Japan. The Imperial Court planned to oust the Sonjo Group by force, and in the coup of August 18, the Satsuma clan and the Aizu clan joined forces to expel the Choshu clan as well as the court nobles of the Sonjo Group. Then an advisory council was formed by Keiki HITOTSUBASHI, who supported Kobu gattai, Katamori MATSUDAIRA (Head of the Aizu clan), who was the Military Commissioner of Kyoto, Shungaku MATSUDAIRA (former Head of the Fukui clan), Yodo YAMAUCHI (former Head of the Tosa clan), Munenari DATE (former Head of the Uwajima clan) and Hisamitsu SHIMAZU.

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. Following the opinion of clans such as Tosa, the Shogunate returned the ruling power to the Imperial Court, and the idea of giving political power to the council of representatives from various clans, which would reform the Shogunate system, was recommended. The ruling power was relinquished by Yoshinobu (formerly Keiki) TOKUGAWA, who had become the 15th Shogun but the anti-Shogunate movement became more dominant with the restoration of Imperial rule and the establishment of the national political council held at Kogosho in Kyoto.