After the Muromachi period, shugo daimyo started the custom of granting unofficial names of government post without official Ikai (Court rank) and Jimoku (appointment ceremonies) from the Imperial Court, to vassals and hikan (low-level bureaucrats) who had made military exploits.
室町時代以降、守護大名の間において武功ある家臣や被官に対して、朝廷の正式な位階や除目の伴わない、非公式な官名を授ける風習が生まれる。