The 17th head, Yoshihiro (1535–1619), was the daimyō at the time of the Battle of Sekigahara, the establishment of the Tokugawa Shogunate, and the Siege of Osaka.

[4] He held significant power during the first two decades of the 17th century, and organized the Shimazu invasion of the Ryūkyū Kingdom (modern-day Okinawa Prefecture) in 1609.

Some retainer families, such as the Ijuin and Shirakawa, were determined to defeat any opposition to help expand the power of the Shimazu clan.

The Shimazu are also famous for being the first to use teppo (firearms, specifically matchlock arquebuses) on the battlefield in Japan, and began domestic production of the weapons as well.

Their tactics included the luring of the opposition into an ambush on both sides by arquebus troops, creating panic and disorder.

[7] Incorporates information from the Japanese Wikipedia article [8] The Shimazu shichi-tō comprised the seven most significant vassal families—the Niiro, Hokugō, Ijuin,[15] Machida, Kawakami, Ata and Kajiki.