Ikeda Tsuneoki

Ikeda Tsuneoki (1536–1584) was a Sengoku daimyo who possessed a special relationship with Oda Nobunaga as his milk brother (the son of Nobunaga's wet nurse), and contributed deeply to Nobunaga's campaign for unification. After the Honnō-ji Incident, he became a powerful ally of Toyotomi Hideyoshi, but lost his life at the Battle of Komaki-Nagakute (1584).

Tsuneoki was a "milk brother," raised by Yōtokuin, his mother and Nobunaga's wet nurse, and from his childhood built an intimate relationship with Nobunaga. The bond of milk brotherhood signified in feudal society a relationship of special trust separate from lord-vassal relations, and Tsuneoki received exceptional confidence from Nobunaga. From Nobunaga's early campaigns onward, he accompanied Nobunaga through numerous battles—the Battle of Okehazama (1560), the Battle of Anegawa (1570), and the Battle of Nagashino (1575)—accumulating distinguished service on many battlefields.

After the Honnō-ji Incident of Tenshō 10 (1582), Tsuneoki took a position supporting Toyotomi Hideyoshi rather than Shibata Katsuie. Through his participation on Hideyoshi's side at the Kiyosu Conference (1582), Tsuneoki became an important pillar of support for Hideyoshi's bid for unification. Though this decision represented a major political gamble, Hideyoshi's faction gained the upper hand through victory at the Battle of Shizugatake (1583), and Tsuneoki solidified his position as a daimyo of Settsu and Mino.

However, at the Battle of Komaki-Nagakute (1584), Tsuneoki clashed with the allied forces of Tokugawa Ieyasu and Oda Nobukatsu at Nagakute in Mikawa Province (present-day Nagakute City, Aichi Prefecture). In this battle, Tsuneoki fell in combat alongside his eldest son, Motosuké. He was 49 years old. While Tsuneoki held a special position as Nobunaga's milk brother, his death on the frontlines symbolizes the transience of the Sengoku warrior.

Regarding his connection to Japanese swords, Tsuneoki, as Nobunaga's milk brother, became intimate with blades from childhood, and records document that he was given famous swords by Nobunaga. As a daimyo governing Settsu and Mino, he maintained deep bonds with the sword-smith traditions of each region. Mino Province, home to the Mino-den blade tradition, was a major center of sword production, and under Tsuneoki's rule, sword culture flourished. Multiple legends survive concerning the blade Tsuneoki wore when he met his end at the Battle of Nagakute, and these have been handed down among sword enthusiasts of later generations. Tsuneoki's life, spent always at Nobunaga's side as his milk brother, embodies the Sengoku period in which blade and the fate of the warrior were one.