The Battle of Fukuda Bay (, Fukudaura no tatakai) in 1565 was the first recorded naval battle between Europeans (the Portuguese) and the Japanese. A flotilla of samurai under the daimy Matsura Takanobu attacked two Portuguese trade vessels that had shunned Matsura's port in Hirado and had gone instead to trade at Fukuda (now within Nagasaki), a port belonging to the rival mura Sumitada. The engagement was part of a process of trial and error by the Portuguese traders to find a safe harbour for their carracks in Japan that eventually brought them to Nagasaki.

A carrack is a three- or four-masted ocean-going sailing ship that was developed in the 14th to 15th centuries in Europe, most notably in Portugal. Evolved from the single-masted cog, the carrack was first used for European trade from the Mediterranean to the Baltic and quickly found use with the newly found wealth of the trade between Europe and Africa and then the trans-Atlantic trade with the Americas. In their most advanced forms, they were used by the Portuguese for trade between Europe and Asia starting in the late 15th century, before eventually being superseded in the 17th century by the galleon, introduced in the 16th century.

In its most developed form, the carrack was a carvel-built ocean-going ship: large enough to be stable in heavy seas, and capacious enough to carry a large cargo and the provisions needed for very long voyages. The later carracks were square-rigged on the foremast and mainmast and lateen-rigged on the mizzenmast. They had a high rounded stern with aftcastle, forecastle and bowsprit at the stem. As the predecessor of the galleon, the carrack was one of the most influential ship designs in history; while ships became more specialized in the following centuries, the basic design remained unchanged throughout this period.