Fearing colonization by Western powers, the Tokugawa shogunate prohibited Spanish and Portuguese ships from entering Japanese ports in the early seventeenth century, largely on account of these countries’ eagerness to spread Christianity. Moreover it issued a ban preventing Japanese citizens from travelling overseas and decreed that ships from other European countries would henceforth only be allowed access to the ports of Nagasaki and Hirado in Kyūshū. Subsequently, in 1641, the Tokugawa shogunate forbade all foreign trade through Hirado, thereby forcing the Dutch trading post there to relocate to the artificial island of Dejima in Nagasaki. Hence, maps and views of Nagasaki, Kyūshū, were much more realistic.