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Jinbō Nagatsuna was a samurai 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...

, and was a cousin of Jinbō Yoshimune of Etchu. Nagatsuna fought in a number of battles against the Nagao clan of Echigo in support of his cousin Yoshimune. However, in 1510, Nagatsuna and his brother Jinbō Nagakiyo

Jinbo Nagakiyo

, was the younger brother of Jinbo Nagatsuna. Reputed to be both a playboy and an alcoholic, he was known to hold raucous parties at his estate in Etchū Province after battle campaigns to celebrate victories. He conspired with Nagao Tamekage against his cousin Jinbō Yoshimune, and is reputed to...

 conspired with 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...

. They were at length discovered and put to death along with most of their families. This is considered to have weakened the Jinbō clan

Jinbo clan

The ' was a Japanese clan that was active in Echigo Province during the Sengoku period, as retainers of the Uesugi clan. During the Edo period, one branch of the Jinbo would enter the service of the Matsudaira clan of Aizu; another would become hatamoto in the service of the Tokugawa shogunate....

in Etchu.