The Kûki family was originally from Muro district of Kii province, and had been settled in Shima province by Kûki Takayoshi. The clan became powerful in the Ago district of Shima and developed a reputation as pirates. Yoshitaka, the eldest son of Kûki Sadataka (a warlord with a reputation for being a pirate), gave his allegiance to Oda Nobunaga when the latter invaded neighboring Ise province in 1569, and commanded a fleet of ships during the Nagashima Campaign (which culminated in the 1574 isolation and annihilation of the Nagashima Ikko-ikki stronghold). Two years later Nobunaga tasked the Kûki with blockading the Ishiyama-Honganji fortress by sea, an operation that resulted in the First Battle of Kizugawaguchi. In that naval contest, the Môri navy, commanded by Murakami Takeyoshi, overwhelmed and defeated Kûki's outclassed fleet and thereby keeping the supply lines to the Honganji open. Nobunaga ordered Yoshitaka to develop some way to counter the Môri naval superiority; his answer was to design a class of enormous, heavily armed warships. These ships, six of which were built, sailed from ports on Shima in 1578 and engaged the Môri navy in the Second Battle of Kizugawaguchi. This time, Yoshitaka was victorious, and the Honganji was successfully blockaded. Following Nobunaga's death in 1582, Kûki served Toyotomi Hideyoshi and was given Toba Castle in Ise. Kûki fought in the Komaki Campaign (1584), assisting Takigawa Kazumasu with the capture of Kanie, one of Oda Nobuo's castles in Ise. Kûki led ships during the Invasion of Kyushu (1587), and in 1590 joined the campaign to subdue the Hojo and teamed with Chosokabe Motochika, Wakizaka Yasuharu, and Kato Yoshiaki in naval maneuvers along the Izu and Sagami coast, including the siege of Shimoda. Kûki went on to command ships during the Invasions of Korea (1592-93, 97-98) and was defeated along with Kato Yoshiaki by the Korean admiral Yi Sun Shin at Angolpo (June 1592). In 1600 Yoshitaka decided to side with Ishida Mitsunari against Tokugawa Ieyasu, and when Ishida was defeated, Yoshitaka committed suicide. His son Moritaka, however, had pragmatically gone off to join Ieyasu, and as the result the Kûki were confirmed in Shima and had their income set at 46,000 koku.