This picture depicts the true view of Nagasaki Port with Dutch trading ships and Chinese junk. Nagasaki was a small fishing village in the 16th century but grew to be one of the most important cities in Japan by the late 17th century. Deshima, also known as Dejima, was a man-made island constructed in Nagasaki harbor by the Tokugawa shogunate (1603-1867) in the mid-1630s. It was the only place in Japan where Westerners, first the Portuguese and then the Dutch, were allowed to reside from the 1630s to 1856 under the country’s policy of national seclusion.
A similar painting of Nagasaki Port by Kawahara Keiga (1786-1860?) is in the collection of Kushu National Museum, (go to https://collection.kyuhaku.jp/gallery/8277.html).