was a samurai of the Uesugi clan

Uesugi clan

The was a Japanese samurai clan, descended from the Fujiwara clan and particularly notable for their power in the Muromachi and Sengoku periods ....

, Kantō Kanrei

Kanrei

or, more rarely, kanryō, was a high political post in feudal Japan; it is usually translated as Shogun's Deputy. After 1349, there were actually two Kanrei, the Kyoto Kanrei and the Kantō Kanrei....

 and shugo

Shugo

was a title, commonly translated as "Governor," given to certain officials in feudal Japan. They were each appointed by the shogun to oversee one or more of the provinces of Japan...

(Constable) of Kōzuke

Kozuke Province

was an old province located in the Tōsandō of Japan, which today comprises Gunma Prefecture. It is nicknamed as or .The ancient provincial capital was near modern Maebashi. During the Sengoku period, Kōzuke was controlled variously by Takeda Shingen, Uesugi Kenshin, the late Hōjō clan, and...

 and Musashi Province

Musashi Province

was a province of Japan, which today comprises Tokyo Prefecture, most of Saitama Prefecture and part of Kanagawa Prefecture. It was sometimes called . The province encompassed Kawasaki and Yokohama...

. His loss of the Izu Province

Izu Province

was a province of Japan in the area of Shizuoka Prefecture. Izu bordered on Sagami and Suruga Provinces. Its abbreviated form name was .The mainland portion of Izu Province, comprising the Izu Peninsula is today the eastern portion of Shizuoka Prefecture and the Izu Islands are now part of...

 to Hōjō Sōun

Hojo Soun

was the first head of the Late Hōjō clan, one of the major powers in Japan's Sengoku period. Born Ise Moritoki, he was originally known as Ise Shinkurō, a samurai of Taira lineage from a reputable family of Shogunate officials...

 in 1492–1498 marked a significant development of Japan's Sengoku period

Sengoku period

The or Warring States period in Japanese history was a time of social upheaval, political intrigue, and nearly constant military conflict that lasted roughly from the middle of the 15th century to the beginning of the 17th century. The name "Sengoku" was adopted by Japanese historians in reference...

.

His deputy (shugo-dai), Nagao Tamekage

Nagao Tamekage

was a retainer of Japanese feudal lord Uesugi Fusayoshi, and a daimyo in his own right, during Japan's Sengoku period. According to some scholars, such as George Bailey Sansom, Nagao Tamekage's career makes him representative of the emergence of the daimyo, and the shift of regional power from the...

, rose up against him in 1510 with the help of Hōjō Sōun, seizing the province and killing Akisada. Sōun, with Tamekage's help, would go on to conquer some of Sagami Province

Sagami Province

was an old province in the area that is today the central and western Kanagawa prefecture. It was sometimes called . Sagami bordered on Izu, Musashi, Suruga provinces; and had access to the Pacific Ocean through Sagami Bay...

, and become one of the most major figures of the Sengoku period; Tamekage's son Uesugi Kenshin

Uesugi Kenshin

was a daimyo who ruled Echigo province in the Sengoku period of Japan.He was one of the most powerful lords of the Sengoku period. While chiefly remembered for his prowess on the battlefield, Kenshin is also regarded as an extremely skillful administrator who fostered the growth of local industries...

would likewise become a major warlord of the period, his rise with the Kantō as the center of his power base, as the result of Akisada's loss, a crucial element to his success.