and Nagakute Campaign proved indecisive and after months of fruitless marches and feints, Hideyoshi and Ieyasu settled the war through negotiations. First, Hideyoshi made peace with Oda Nobukatsu, and then he offered a truce to Ieyasu. The deal was made at the end of the year; as part of the terms Ieyasu's second son, Ogimaru (also known as Yuki Hideyasu) became an adopted son of Hideyoshi. Ieyasu's aide, Ishikawa Kazumasa, chose to join the pre-eminent daimyo and so he moved to Osaka to be with Hideyoshi. However, few other Tokugawa retainers followed this example. Alliance with Hideyoshi Toyotomi Hideyoshi was understandably distrustful of Ieyasu, and five years passed before they fought as allies. The Tokugawa did not participate in Hideyoshi's successful Invasion of Shikoku (1585) and the Kyūshū Campaign (1587). In 1590, Toyotomi Hideyoshi attacked the last independent daimyo in Japan, Hōjō Ujimasa. The Hōjō clan ruled the eight provinces of the Kantō region in eastern Japan. Hideyoshi ordered them to submit to his authority and they refused. Ieyasu, though a friend and occasional ally of Ujimasa, joined his large force of 30,000 samurai with Hideyoshi's enormous army of some 160,000. The Odawara campaign was the first battle of Ieyasu and Hideyoshi as allies. They attacked several castles on the borders of the Hōjō clan with most of their army laying siege to the castle at Odawara. Hideyoshi's and Ieyasu's army captured Odawara Castle after six months (oddly for the time period, deaths on both sides were few). During this siege, Hideyoshi offered Ieyasu a radical deal: He offered Ieyasu the eight Kantō provinces which they were about to take from the Hōjō in return for the five provinces that Ieyasu currently controlled (including Ieyasu's home province of Mikawa). Ieyasu accepted this proposal. Bowing to the overwhelming power of the Toyotomi army, the Hōjō accepted defeat, their leaders committed suicide and Ieyasu marched in and took control of their provinces, ending the clan's reign of over 100 years. The Sannohe faction of Nanbu clan led by Nanbu Nobunao organized a coalition of most of the factions of the Nanbu clan and pledged allegiance to Toyotomi Hideyoshi at the siege of Odawara. In return, he was recognized as chieftain of the Nanbu clan, and confirmed as daimyo of his existing holdings in the northern districts of Mutsu Province. However, Kunohe Masazane (1536–1591), lord of Kunohe Castle and leader of the Kunohe