Moshitsugi, also called sosha/soja, originally referred to a person in charge of conveying messages to the Emperor or Daijo Tenno (the Retired Emperor), and in the Kamakura and Muromachi bakufu it also referred to a person conveying messages to the seii taishogun (literally, "great general who subdues the barbarians"). Moshitsugi in the bakufu also carried out miscellaneous tasks, informed the shogun of the names of people who sought an audience with him, and ushered them to the audience. During the period of the sixth shogun of the Muromachi bakufu, Yoshinori ASHIKAGA, the post was monopolized by the Ise, Ueno, Odachi and Hatakeyama clans, and they took charge of Moshitsugi in turn, forming a group composed of several persons working in shifts. They were called Moshitsugishu, and later this became a term referring to the rank of the family, ranked after Oshobanshu (officials who accompany shogun), Otomoshu (group who attended the shogun to the ancient capital Kyoto), Oheyashu (the position in charge of keeping night watch over the shogun's bedchamber).
Nowadays, Moritoki ISE (Soun HOJO) is considered to have been one of the Moshitsugishu.