Uesugi Tomosada (1525–1546), also known as Ōgigayatsu Tomosada (扇ヶ谷朝定), was a samurai

Samurai

is the term for the military nobility of pre-industrial Japan. According to translator William Scott Wilson: "In Chinese, the character 侍 was originally a verb meaning to wait upon or accompany a person in the upper ranks of society, and this is also true of the original term in Japanese, saburau...

 commander of the Ōgigayatsu branch 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 ....

 around the middle 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...

.

The eldest legitimate son of Uesugi Tomooki

Uesugi Tomooki

was a lord of Edo Castle and enemy of the Hōjō clan, who seized the castle in 1524. He was the son of Uesugi Tomoyoshi, who was among the first to oppose the Hōjō's rise to power....

 of Ōgigayatsu, following his father's death in 1537, though he was still a child, Tomosada led an attack on the Late Hōjō clan

Late Hojo clan

The ' was one of the most powerful warrior clans in Japan in the Sengoku period and held domains primarily in the Kantō region.The clan is traditionally reckoned to be started by Ise Shinkurō, who came from a branch of the prestigious Ise clan, a family in the direct employment of the Ashikaga...

 in the Tachibana district of 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...

. He established himself in the temple of Kandai-ji, which he fortified as a castle. Hōjō Ujitsuna

Hojo Ujitsuna

was the son of Hōjō Sōun, founder of the Go-Hōjō clan. He continued his father's quest to gain control of the Kantō ....

 took Kawagoe castle

Kawagoe castle

' is a flatland Japanese castle in the city of Kawagoe, in Japan's Saitama Prefecture. It is the closest castle to Tokyo to be accessible to visitors, as Edo castle is now the Imperial palace, and largely inaccessible....

 soon afterwards from Tomosada's uncle, Uesugi Tomonari, however.

In the 1546 battle of Kawagoe

Battle of Kawagoe

The 1545-1546 ' was part of a failed attempt by the Uesugi clan to regain Kawagoe Castle from the Late Hōjō clan in the sengoku period of Japan...

, Tomosada allied itself with Ashikaga Haruuji and Uesugi Norimasa

Uesugi Norimasa

was a daimyō of feudal Japan, and held the post of Kantō Kanrei, the Shogun's deputy in the Kantō. He is perhaps best known as the adoptive father of Uesugi Kenshin, one of the most famous warlords in Japanese history....

 of Yamauchi against Hōjō Ujitsuna and Hōjō Ujiyasu

Hojo Ujiyasu

was the son of Hōjō Ujitsuna and a daimyō of the Odawara Hōjō clan.Upon his father's death in 1541, a number of the Hōjō's enemies sought to take advantage of the opportunity to seize major Hōjō strongholds...

. He was killed in battle, and the attempt to regain the castle for the Uesugi was ultimately unsuccessful.

With Tomosada's death, the Ōgigayatsu branch came to an end.