was a general under the Sengoku period daimyō, and later shōgun, Tokugawa Ieyasu. He is regarded as one of the Four Guardians of the Tokugawa along with Honda Tadakatsu, Sakakibara Yasumasa, and Sakai Tadatsugu. He led the clan after the death of his foster mother, Ii Naotora. He married Tobai-in, Matsudaira Yasuchika's daughter and adopted daughter of Tokugawa Ieyasu. Early life Ii Naomasa was born in Hōda Village of Tōtōmi Province. His childhood name was Toramatsu (虎松) later Manchiyo (万千代). His family, like the Tokugawa, had originally been retainers of the Imagawa clan, but following the death of the clan's leader, Imagawa Yoshimoto, in the Battle of Okehazama (1560), confusion and general chaos ensued. Naomasa's father, Ii Naochika, was falsely convicted of treason by Yoshimoto's paranoid successor, Imagawa Ujizane, and was subsequently killed. Naomasa, then a very small child, was personally lucky to escape his father's fate. After many difficulties, Ii Naotora succeeded the Ii clan and acted as the guardian of Naomasa; she adopted Naomasa to later succeed her. When Ii Naotora began working with Tokugawa Ieyasu after visiting him in Hamamatsu, she sent Naomasa to his care. Service under Ieyasu Ii Naomasa joined the ranks of the Tokugawa clan in the mid-1570s, rising swiftly through the ranks to eventually become the master of a sizable holding in Ōmi Province, following the Battle of Sekigahara (1600). His court title was Hyōbu-dayū. Naomasa distinguished military service against the Takeda clan, at Siege of Takatenjin (1581), and for killing ninja who had been sneaking in to the bedroom of Ieyasu. Naomasa accompanied Ieyasu returned to Mikawa from Sakai, where he had been staying, crossing over Iga province, following the death of Oda Nobunaga at Honnoji Incident (1582). Naomasa initially garnered mass attention at the Battle of Nagakute (1584), commanding around three thousand musketeers with distinction and defeating the forces led by Ikeda Tsuneoki. In the battle, Naomasa fought so valiantly that it elicited praise from Toyotomi Hideyoshi, who was on the opposing side. Following the battle, Hideyoshi's mother was sent to stay with Naomasa in genteel captivity, cementing an alliance between the Tokugawa and the Toyotomi. After Naomasa helped ensure victory during the siege of Odawara (1590) by breaching the castle walls and contributing to the Hōjō clan's surrender, he was given Minowa Castle in Kōzuke and 120,000 koku, the largest amount of land owned by any of the Tokugawa retainers.