It was originally used interchangeably with the term 'monzeki' but later came to indicate a rank that was subordinate to and aided the monzeki, which was a stage that was required before one could be promoted to the states of monzeki.
当初は「門跡」と混同して用いられていたが、後には門跡に次いでこれを補佐する身分とされて門跡に就任するための要件とも考えられるようになった。