We can find a good instance of pirates’ maneuvering behavior in the tug-of-wars over Motobuto Castle. The castle was located in Honjo, Kojima County, Bizen Province. Kojima used to be an island in ancient times. The island was between Bizen Province in the mainland Japan and Sanuki Province in Shikoku Island. It was also between Bizen and Bicchu Provinces and was an important water transportation center in the Eastern Seto Inland Sea. Although Kojima had become a peninsula with a sandbar by sometime in medieval times, the strategic importance of Motobuto Castle kept unchanging.
Although Kojima was in Bizen Province, it was under the hegemony of the Hosokawa Clan, which produced provincial guardian samurais in Sanuki and Awa Provinces in Shikoku Island. The castle itself and its surrounding domain were managed by the Kozai Family.
In 1567, the Mori Clan and No-shima Murakami Pirates invaded Motobuto Castle. Shima Yoshitoshi (?-1602), a member of the pirates, killed Kozai Matagoro (?-1567) in the battle, and was appointed to be the lord of the castle.