Oshu Tandai (奥州探題)

Oshu tandai was the office of special administrators to the shogun in the Muromachi and the Sengoku period (of Japan). It replaced the former shugo (military governor). Oshu generally refers to Mutsu Province (the Prefectures of Aomori, Iwate, Miyagi and Fukushima). Dewa Province (the Prefectures of Akita and Yamagata) is commonly called Ushu. Ou is usually used to refer to the two provinces which are now called Tohoku region.

Oshu tandai's predecessors were Oshu sotaisho (Supreme Commander of Oshu) and Oshu kanrei (Shogunal Deputy of the Northern Region). In 1392 Yoshimitsu ASHIKAGA the 3rd shogun reconciled with the Kamakura kubo (Kamakura governor-general) Ujimitsu ASHIKAGA. Both the Provinces of Mutsu and Dewa were added to the Kamakura Bakufu's territories and the office of Oshu kanrei was abolished. It became mandatory for the kokujin (provincial warriors) in the provinces to wait upon the Kamakura government. In 1399 the Kamakura kubo Mitsukane ASHIKAGA sent his two younger brothers, Mitsusada ASHIKAGA as Inamura Gosho (Palace) and Mitsunao ASHIKAGA as Sasagawa Gosho (Palace) to the provinces. By this time the relationship between the shogun and the Kamakura kubo considerably deteriorated. The Ashikaga shogunate directly appointed the powerful kokujin who were opposed to the Kamakura government in Kanto and Oshu to Kyoto fuchishu (a corps of special support troops in Kyoto), to compete with the Kamakura kubo. In 1400 it appointed Akimochi OSAKI as Oshu tandai. The office had since become hereditary to the Osaki clan.

In Oshu, However, the prominent kokujin had had the authority, which was as powerful as that of the shugo, to request military forces, to issue and recommend the issuance of gunchujo (service citations) and to dispatch envoys under the command of the shogunate. Furthermore the southern part of the province was governed by the Sasagawa and the Inamura Gosho who represented the Kamakura government. The province was internally controlled by the Date and the Ashina clan who as Kyoto fuchishu had direct ties with the shogunate. The Osaki clan had no chance of dominating the province. The prominent kokujin gradually made the areas they governed into their own territories. They were on their way to warring daimyo (territorial lords). To counteract such moves, the Osaki clan also appropriated the area they directly controlled as their own domain. They were reduced to the position of a powerful kokujin.

In 1514 Tanemune DATE was appointed to the office of shugo in Mutsu Province. This practically brought an end to the office of Oshu tandai, the hereditary post of the Osaki clan. Prevailing over the Osaki clan, the Date clan came to dominate the latter. Oshu tandai had become the Data clan's hereditary post since Harumune DATE, son of Tanemune was appointed in 1555. Masamune DATE (Harumune's grandson) who became lord of the clan after the collapse of the Muromachi shogunate called himself Oshu tandai. In 1590 he became a vassal of the Toyotomi administration and gave up the title of Oshu tandai. On the other hand, the Osaki clan who did not declare to serve Hideyoshi TOYOTOMI were defeated by the latter. This terminated the office of Oshu tandai in name and reality.

From 1350 to 1360 Kaneyori SHIBA, son of Kaneie SHIBA was posted in Dewa as Azechi (local inspector) of the province. Later he was called "Ushu tandai" and his descendants called themselves the Mogami clan.