<P> The Korean side of the river was heavily industrialized during the period of Japanese rule ( 1910 -- 1945 ) , and by 1945 almost 20 % of Imperial Japan 's total industrial output originated in Korea . During the Korean War , the movement of United Nations troops approaching the river precipitated massive Chinese intervention from around Dandong . In the course of the conflict every bridge across the river except one was destroyed . The one remaining bridge was the Sino -- Korean Friendship Bridge connecting Sinuiju , North Korea to Dandong , China . During the war the valley surrounding the western end of the river also became the focal point of a series of dogfights for air superiority over North Korea , earning the nickname `` MiG Alley '' in reference to the MiG - 15 fighters flown by the combined North Korean , Chinese and Soviet forces . </P>
<P> The Korean side of the river was heavily industrialized during the period of Japanese rule ( 1910 -- 1945 ) , and by 1945 almost 20 % of Imperial Japan 's total industrial output originated in Korea . During the Korean War , the movement of United Nations troops approaching the river precipitated massive Chinese intervention from around Dandong . In the course of the conflict every bridge across the river except one was destroyed . The one remaining bridge was the Sino -- Korean Friendship Bridge connecting Sinuiju , North Korea to Dandong , China . During the war the valley surrounding the western end of the river also became the focal point of a series of dogfights for air superiority over North Korea , earning the nickname `` MiG Alley '' in reference to the MiG - 15 fighters flown by the combined North Korean , Chinese and Soviet forces . </P>
when did un troops approach the yalu river
when did un troops approach the yalu river
During the Korean War
During the Korean War