born Jan. 31, 1543, Okazaki, Japan
died June 1, 1616, Sumpu
Founder of the Tokugawa shogunate (see Tokugawa period ) and ruler of Japan (1603–16).
Along with Oda Nobunaga and Toyotomi Hideyoshi , Ieyasu was one of the three unifiers of premodern Japan. He allied himself initially with Nobunaga; that alliance allowed Ieyasu to survive the vicissitudes of endemic warfare in Japan at that time and to slowly build up his territory. By the 1580s he had become an important daimyo in control of a fertile and populous han (domain). When Nobunaga died, Ieyasu offered a vow of fealty to Hideyoshi, who was extending his control over southwestern Japan; Ieyasu, meanwhile, enlarged his vassal force and increased his domain's productivity. In the 1590s he avoided participating in Hideyoshi's disastrous expeditions to Korea, instead consolidating his position at home. When Hideyoshi died, Ieyasu had the largest and most reliable army and the most productive and best-organized domain in Japan; he emerged as victor from the ensuing power struggle. He confiscated his enemies' lands and gave them new domains away from Japan's heartland, much of which became Tokugawa property. He received the title of shogun and two years later passed the title to his son, thereby establishing it as hereditary among the Tokugawa.