port city on w. Kyushu Island; second oldest port in Japan, and only port permitted by Tokugawa shogunate between 1639 and 1859; capital and largest city of Nagasaki prefecture; second city to be struck by U.S. atomic bomb in World War II; device dropped on Aug. 9, 1945, killed almost 40,000 people and destroyed about 40 percent of the city; rebuilt after the war, became an important tourist center and spiritual home for movements to ban nuclear weapons; pop. 445,900