Toyotomi Hidenaga (豊臣 秀長, April 8, 1540 – February 15, 1591), formerly known as Hashiba Koichirō (羽柴 小一郎) was a half-brother of Toyotomi Hideyoshi, one of the most powerful (and significant) warlords of Japan's Sengoku period. He was also known by his court title, Dainagon (大納言). After participating in and helping Hideyoshi win the battle at Kii, Hidenaga oversaw the construction of Wakayama Castle in 1585, appointing Tōdō Takatora to the chief engineer. He led Hideyoshi's vanguard force a few years later into Satsuma Province, contributing heavily to his half-brother's victories in gaining control of Kyūshū. Hidenaga was rewarded the provinces of Kii, Izumi and Yamato, reaching a governance of one million koku. He was regarded as Hideyoshi's brain and right-arm. He died in Yamato Kōriyama, Nara, and his grave there is at Dainagon-zuka (大納言塚).