Obata Kagenori (1572-1663), also known as Obata Dōgyū, was a Confucian scholar and samurai retainer of the Takeda clan during 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...

. He is perhaps most well-known for his completion of the Kōyō Gunkan

Koyo Gunkan

The ' is a record of the military exploits of the Takeda family, compiled largely by the Takeda vassal Kōsaka Danjō Masanobu, and completed in 1616 by Obata Kagenori...

, the chronicle of the Takeda clan's military campaigns begun by Kōsaka Masanobu

Kosaka Masanobu

also known as was one of Takeda Shingen's most loyal retainers, and one of his "Twenty-Four Generals" during the Sengoku period of Japan. He is often credited as the original author of Kōyō Gunkan, which records the history of the Takeda family and their military tactics...

, and for founding the Kōshū-ryū Gungaku, a school for studying the arts of war.

Kagenori was the third son of Obata Masamori

Obata Masamori

Obata Masamori , also known as Obata Nobusada, was one of Takeda Shingen's 'Twenty-four Generals', his most trusted commanders. He was the son of Obata Toramori, and came from western Kozuke province. He fled Kozuke and joined the Takeda around 1560...

, and fought under Tokugawa Ieyasu

Tokugawa Ieyasu

 was the founder and first shogun of the Tokugawa shogunate of Japan , which ruled from the Battle of Sekigahara  in 1600 until the Meiji Restoration in 1868. Ieyasu seized power in 1600, received appointment as shogun in 1603, abdicated from office in 1605, but...

 at the battle of Sekigahara

Battle of Sekigahara

The , popularly known as the , was a decisive battle on October 21, 1600 which cleared the path to the Shogunate for Tokugawa Ieyasu...

 in 1600, and at the siege of Osaka

Siege of Osaka

The was a series of battles undertaken by the Tokugawa shogunate against the Toyotomi clan, and ending in that clan's destruction. Divided into two stages , and lasting from 1614 to 1615, the siege put an end to the last major armed opposition to the shogunate's establishment...

fifteen years later.