Around the time of the Silla dynasty in Korea, Japan became a unified country under an emperor. For much of Japan's history, however, the emperor's weren't strong. Powerful military leaders, shoguns, controlled Japan's government.
The Korean War
Ships from Europe first arrived in Japan and Korea around 1600. Both kingdoms decided to keep Western merchants and missionaries away.
Japan's new leaders expanded its industry and military. They also increased its power in the region.
Japan's control of Korea ended after Japan surrendured at the end of World War II. At the same time, the United States occupied the southern part of Korea.