was a Japanese samurai of the late 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...

, a senior retainer of the Azai clan of Ōmi Province

Omi Province

is an old province of Japan, which today comprises Shiga Prefecture. It was one of the provinces that made up the Tōsandō circuit. It is nicknamed as .Lake Biwa, Japan's largest lake, is located at the center of the province...

. Together with Kaihō Tsunachika and Amemori Yahei, Kiyotsuna was known as one of the . Kiyotsuna served three generations of the Azai lords: Sukemasa

Azai Sukemasa

built Odani Castle for the Azai clan, including his son Azai Hisamasa, to rule.Sukemasa was a former Samurai under the Kyōgoku clan, but he gradually increased his power under an internal struggle within the clan. He managed to become daimyo, a powerful feudal ruler, but became engaged in a...

, Hisamasa

Azai Hisamasa

was a son of Azai Sukemasa and the second head of the Azai clan.Hisamasa became the head of the clan in 1542 after his father died, but unlike his father, he was never a strong leader. Losing domains against Rokkaku clan, he instead became a Rokkaku retainer...

, and Nagamasa

Azai Nagamasa

was a Daimyo during the Sengoku period of Japan. His clan, the Azai, were located in northern Ōmi Province, east of Lake Biwa. He was both the brother-in-law of Oda Nobunaga, starting in 1564, and one of Nobunaga's enemies from 1570-1573. Nagamasa and his clan were utterly destroyed by Oda...

. As a mark of the Azai family's deep trust of Akao, he was allowed to maintain a residence within Odani Castle

Odani Castle

was a Sengoku period mountain-top castle located in the present day town of Kohoku in Higashiazai District, Shiga Prefecture, Japan. Only the ruins remain today. It was the home castle of the Azai clan and the mountain it was built upon was considered to be impregnable...

.

Kiyotsuna was imprisoned after the fall of Odani Castle

Odani Castle

was a Sengoku period mountain-top castle located in the present day town of Kohoku in Higashiazai District, Shiga Prefecture, Japan. Only the ruins remain today. It was the home castle of the Azai clan and the mountain it was built upon was considered to be impregnable...

, and beheaded by Nobunaga. However, Nobunaga spared the life of Kiyotsuna's son Kiyofuyu.