Appointment (Ninkan) (任官)
Ninkan means being appointed to a government post. Ninkan is a term which was formerly used in the Japanese government-regulated organisations since the implementation of the Ritsuryo system in the Nara era and is still used today in the government and state institutions. Nowadays ninkan is used when appointing government officials, especially judges, public prosecutors, Self-Defense force officials (including rapid-reaction reserve officials and reserve officials), police officers and Maritime Safety officials. The antonym of ninkan is menkan (dismissal) and taikan (retirement).
A related term is ninkankyohi, which means refusal of appointment. As a rule, ninkankyohi is used in the case when somebody who passed the bar examination refuses to be appointed as a judge or when somebody graduates from the National Defense Academy refuses to get appointed as a Self-Defense force official. When government officials transfer to a different government office or workplace, the term tenkan is used.
Appointment under the Ritsuryo system
Under the Ritsuryo system the rank of government posts (kanshoku) were decided upon court ranks (ikai), which were nondivisable and called kan-i (official court ranks). Basically, one was appointed to a government post according to his court rank, which was called kanisoto sei (the ranks of the bureaucracy system). At the appointment ceremony "jimoku", held by personnel of the Imperial court, court ranks and posts were often given at the same time.
Since the Kamakura period, as a general rule, the conferments of a court rank and appointment to an office of samurai who were shogunal retainers were reported to the Imperial Court via the lord of Kamakura, and it was strictly prohibited for the shogunal retainers to receive a rank and office directly from the Imperial Court. It was intended to prevent shogunal retainers from having a direct relation with the Imperial Court because the master of shogunal retainers was the lord of Kamakura, who held the bakufu, and the bakufu feared that a direct relation between shogunal retainers and the Imperial Court might lead to estrangement or independence of shogunal retainers. When this prohibition was violated and a shogunal retainer received a rank or post directly (not via the Kamakura shogunate) or without permission, that was called Jiyuninkan. In order to put appointments of posts (ninkan) under the control of the shogun, Kanto-bugyo (a commissioner of the appointment to an office) was set up in the shogunate, who acted as a contact for samurai families (buke), who applied for ninkan.
Actually there were a case in which 24 shogunal retainers of the eastern provinces (Togoku) inclulding MINAMOTO no Yoshitsune in the time of MINAMOTO no Yoritomo, were appointed directly and were forbidden to go east of Sunamoto (Gifu).