Isono Kazumasa (磯野員昌)

Kazumasa ISONO (dates of birth and death unknown) was a Japanese military commander who lived from the Sengoku period (Japan) to the Azuchi-Momoyama period. He served the Azai clan and subsequently, the Oda clan.
Tanba no kami (the governor of Tanba Province)
He is known by his heroic act during the Battle of Anegawa. After having surrendered to Nobunaga ODA, he was assigned to reign over Takashima County, but was exiled.

The Isono clan had been the Kyogoku clan's vassal for generations, but served under the Azai clan involuntarily. Sawayama-jo Castle-based Kazukichi ISONO adopted Kazumasa's father Kazumune who was of a branch family of the Isono. The head family of the Isono, who was based in Isonoyama-jo Castle, was destroyed by Sukemasa AZAI.

Kazumasa, who was based in Sawayama-jo Castle, frequently achieved military exploits because of his military prowess in the battles against the Rokkaku clan and served as the spearhead of the Azai army corps.

Battle of Anegawa
In the Battle of Anegawa in June 28, 1570, he penetrated deep into the Oda camp and closed in on Nobunaga ODA's headquarter. However, because Ittetsu INABA, a military commander on the Oda side, and some others, who were on standby, rushed to rescue Nobunaga and Ieyasu TOKUGAWA's army which defeated the Asakura's army later joined the Oda's army, the Azai side was put to rout.

Kazumasa's vigorous attack closing in on Nobunaga's headquarters is recorded as 'Kazumasa no Anegawa juichidan kuzushi' (Kazumasa's destruction of eleven rows of Oda's military formation in the battle of Anegawa)
However, some believe that the episode was written after the Tokugawa clan unified Japan to dramatize the Tokugawa army's military performance, while other believe that the Oda clan's documents did not record the episode because Kazumasa, who surrendered to the Oda clan, was later exiled from the clan. Whether the episode is true or not, it is probably true that he was a military commander of bravery who deserves to be talked about by the future generations.

Surrendered to the Oda clan
As soon as the Battle of Anegawa ended, Sawayama-jo Castle was besieged by the Oda army. The land routes were cut by the Oda army based in Yokoyama-jo Castle. Believing Hideyoshi's allegation about Kazumasa's side switching, the Azai side stopped supplying army provisions and soldiers to Sawayama-jo Castle by lake. Because of this, Kazumasa surrendered to Nobunaga when Sawayama-jo Castle was attacked on February 24, 1571.

It can be said that Hideyoshi's tactic was very skillful considering that the Isono clan served under the Azai clan involuntarily and that Kazumasa himself was independent-minded. Afterward, Kazumasa gained Nobunaga's favor and was honored to be assigned to reign over Takashima County, Omi Province. He suppressed Ikko sect's revolt in Echizen Province, and was engaged in the arrest of Zenjubo SUGITANI and other cases.

However, in February 3, 1578, he displeased Nobunaga, who deprived him of the territory and exiled him to Mt. Koya. Takashima County was given to Nobusumi TSUDA who was of the Oda family. The details about the incident is unclear, but according to one theory, Nobunaga told Kazumasa to transfer the head of family to Nobusumi, Kazumasa's adopted son, but he refused. The details about Kazumasa after his exile are unclear. Some believe that he returned to Takashima County to engage in farming after the Honnoji Incident and died in 1590. The family after his generation served Mitsunari ISHIDA and subsequently Takatora TODO to save the family name. His grandson Yukinao ISONO joined the TODO army in the Siege of Osaka. He was credited with killing Moritsugu MASHITA during the Battle of Yao and Wakae.

[Original Japanese]