Kōbu gattai

Kōbu gattai (Japanese: 公武合体, Union of the Imperial Court and the Shogunate) was a policy in Bakumatsu Japan aiming at obtaining a political coordination between the Bakufu and the Imperial Court.

The policy was adopted following the murder of the Prime Minister Ii Naosuke in 1860. The assassination, combined with the popular upheaval against foreign encroachment, forced the Bakufu to soften its political stance, and to adopt the compromise policy of Kōbu Gattai upon the suggestion of the Satsuma and Mito Domains. In the following years, the Shogunate and the Imperial court would vie for political supremacy.

...
Wikipedia