Ch. 1. Northernmost region, incorporated during Joseon era into Korean political rule; source of Koreans migrants crossing into Manchuria and Russia since the 19th century; site of some anti-Japanese guerrilla activity in 1930s and 1940s.
Chs. 1, 7, 19. Concentration of wartime industrial growth in late 1930s and early 1940s.
Ch. 1. Site of the Great Battle of Salsu River, 612; approximate northern boundary of Unified Silla