title: Korean War
paragraph_text: UN forces retreated to Suwon in the west, Wonju in the center, and the territory north of Samcheok in the east, where the battlefront stabilized and held. The PVA had outrun its logistics capability and thus were unable to press on beyond Seoul as food, ammunition, and matériel were carried nightly, on foot and bicycle, from the border at the Yalu River to the three battle lines. In late January, upon finding that the PVA had abandoned their battle lines, General Ridgway ordered a reconnaissance-in-force, which became Operation Roundup (5 February 1951). A full-scale X Corps advance proceeded, which fully exploited the UN Command's air superiority, concluding with the UN reaching the Han River and recapturing Wonju.
title: Korean War
paragraph_text: By August, the KPA had pushed back the ROK Army and the Eighth United States Army to the vicinity of Pusan in southeast Korea. In their southward advance, the KPA purged the Republic of Korea's intelligentsia by killing civil servants and intellectuals. On 20 August, General MacArthur warned North Korean leader Kim Il-sung that he was responsible for the KPA's atrocities. By September, the UN Command controlled the Pusan perimeter, enclosing about 10% of Korea, in a line partially defined by the Nakdong River.
title: Naktong Vallis
paragraph_text: Naktong Vallis is an ancient river valley in the Arabia quadrangle of Mars, located at 5.3 degrees north latitude and 327.1 degrees west longitude. It is 670 km long and was named after the Nakdong River in Korea.
title: Linjiang Yalu River Bridge
paragraph_text: The Linjiang Yalu River Bridge () is a bridge over the Yalu River, connecting Linjiang City, Jilin Province, China, with Chunggang County, Chagang Province, North Korea. It was built by the Japanese in 1938 and Linjiang Border Post is located there. A little downstream from the bridge is Yunfeng Dam.
title: Korean War
paragraph_text: After the first two months of the conflict, South Korean forces were on the point of defeat, forced back to the Pusan Perimeter. In September 1950, an amphibious UN counter-offensive was launched at Inchon, and cut off many of the North Korean attackers. Those that escaped envelopment and capture were rapidly forced back north all the way to the border with China at the Yalu River, or into the mountainous interior. At this point, in October 1950, Chinese forces crossed the Yalu and entered the war. Chinese intervention triggered a retreat of UN forces which continued until mid-1951. After these dramatic reversals of fortune, which saw Seoul change hands four times, the last two years of conflict became a war of attrition, with the front line close to the 38th parallel. The war in the air, however, was never a stalemate. North Korea was subject to a massive bombing campaign. Jet fighters confronted each other in air-to-air combat for the first time in history, and Soviet pilots covertly flew in defense of their Communist allies.
title: Usi County
paragraph_text: Usi County is a "kun", or county, in westernmost Chagang Province, North Korea. It looks across the Yalu River into the People's Republic of China. Within North Korea, it borders Chosan and Kopung to the east, Songwon to the south, and North Pyongan Province's Pyoktong county to the west. Originally part of Pyoktong, it was made a separate county in 1952 as part of a general reorganization of local government; in 1954, it was transferred from North Pyongan to Chagang.
title: Korean War
paragraph_text: After secretly crossing the Yalu River on 19 October, the PVA 13th Army Group launched the First Phase Offensive on 25 October, attacking the advancing UN forces near the Sino-Korean border. This military decision made solely by China changed the attitude of the Soviet Union. Twelve days after Chinese troops entered the war, Stalin allowed the Soviet Air Force to provide air cover, and supported more aid to China. After decimating the ROK II Corps at the Battle of Onjong, the first confrontation between Chinese and U.S. military occurred on 1 November 1950; deep in North Korea, thousands of soldiers from the PVA 39th Army encircled and attacked the U.S. 8th Cavalry Regiment with three-prong assaults—from the north, northwest, and west—and overran the defensive position flanks in the Battle of Unsan. The surprise assault resulted in the UN forces retreating back to the Ch'ongch'on River, while the Chinese unexpectedly disappeared into mountain hideouts following victory. It is unclear why the Chinese did not press the attack and follow up their victory.
title: Korean War
paragraph_text: On 15 October 1950, President Truman and General MacArthur met at Wake Island in the mid-Pacific Ocean. This meeting was much publicized because of the General's discourteous refusal to meet the President on the continental United States. To President Truman, MacArthur speculated there was little risk of Chinese intervention in Korea, and that the PRC's opportunity for aiding the KPA had lapsed. He believed the PRC had some 300,000 soldiers in Manchuria, and some 100,000–125,000 soldiers at the Yalu River. He further concluded that, although half of those forces might cross south, "if the Chinese tried to get down to Pyongyang, there would be the greatest slaughter" without air force protection.
title: Yalu River
paragraph_text: 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.
title: United States in the Korean War
paragraph_text: At the conclusion of World War II the Allied nations began the process of disarmament of Axis controlled regions. Japan occupied Korea at this time and had been in control since 1910. In 1945, the decision was made to have American Marines forces oversee Japanese surrender and disarmament south of the 38th parallel and the Soviet Union would facilitate the change of power to the north. At the time there was no political motivation and seemed to be a logical and convenient plan of action. The original agreement and intent was to create a unified and independent Korea out of the post Japanese occupation era. Instead each side of the 38th parallel established its own government under the influence of the occupational country; the United States in South Korea and the Soviet Union in North Korea. Both new Korean governments discredited the other and claimed to be the only legitimate political system. Tensions between the North and South escalated and each side began to petition foreign powers for resources and support. South Korea wanted weapons and supplies from Truman and the United States government while North Korea sought help from Stalin and the Soviet Union. The United States was still war weary from the disruptive World War II campaign and refused South Korea's request for weapons and troops. North Korea convinced the Soviet Union to supply them with the weapons and support they requested. This decision coincided with the United States withdrawing the last remaining combat troops from South Korea. North Korea saw its opportunity and attacked South Korean forces at the 38th parallel on June 25, 1950 and thus initiating the Korean War.
title: Korean War
paragraph_text: In contrast, the ROK Army defenders were relatively unprepared and ill-equipped. In South to the Naktong, North to the Yalu (1961), R.E. Appleman reports the ROK forces' low combat readiness as of 25 June 1950. The ROK Army had 98,000 soldiers (65,000 combat, 33,000 support), no tanks (they had been requested from the U.S. military, but requests were denied), and a 22-piece air force comprising 12 liaison-type and 10 AT6 advanced-trainer airplanes. There were no large foreign military garrisons in Korea at the time of the invasion, but there were large U.S. garrisons and air forces in Japan.
title: Geomdeok mine
paragraph_text: The Geomdeok mine is one of the largest lead and zinc mines in North Korea and in the world. The mine is located in the center of the country in South Hamgyong Province. The mine has estimated reserves of 266 million tonnes of ore 0.88% lead and 4.21% zinc .
title: North Korea
paragraph_text: North Korea (Korean: ; MR: "Chosŏn" or literally ; MR: "Pukchosŏn"), officially the Democratic People's Republic of Korea (DPRK or DPR Korea; Korean: , "Chosŏn Minjujuŭi Inmin Konghwaguk"), is a country in East Asia constituting the northern part of the Korean Peninsula, with Pyongyang the capital and the largest city in the country. To the north and northwest, the country is bordered by China and by Russia along the Amnok (known as the Yalu in Chinese) and Tumen rivers and to the south it is bordered by South Korea, with the heavily fortified Korean Demilitarized Zone (DMZ) separating the two. Nevertheless, North Korea, like its southern counterpart, claims to be the legitimate government of the entire peninsula and adjacent islands.
title: Korean War
paragraph_text: After a new wave of UN sanctions, on 11 March 2013, North Korea claimed that it had invalidated the 1953 armistice. On 13 March 2013, North Korea confirmed it ended the 1953 Armistice and declared North Korea "is not restrained by the North-South declaration on non-aggression". On 30 March 2013, North Korea stated that it had entered a "state of war" with South Korea and declared that "The long-standing situation of the Korean peninsula being neither at peace nor at war is finally over". Speaking on 4 April 2013, the U.S. Secretary of Defense, Chuck Hagel, informed the press that Pyongyang had "formally informed" the Pentagon that it had "ratified" the potential usage of a nuclear weapon against South Korea, Japan and the United States of America, including Guam and Hawaii. Hagel also stated that the United States would deploy the Terminal High Altitude Area Defense anti-ballistic missile system to Guam, because of a credible and realistic nuclear threat from North Korea.
title: Bukhan River
paragraph_text: The Bukhan River (North Han River) is a tributary of the Han River that flows through both North and South Korea. It traverses Kangwon province in North Korea and Gangwon and Gyeonggi provinces in South Korea.
title: Chunggang County
paragraph_text: Chunggang County is a "kun", or county, in northern Chagang province, North Korea. It was originally part of Huchang county in Ryanggang, and for that reason older sources still identify it as being part of Huchang. The county seat was originally known as Chunggangjin (중강진), but is now known as Chunggang "ŭp". Chunggang looks across the Yalu River at China, and borders Ryanggang province to the south.
title: Korean War
paragraph_text: By 1 October 1950, the UN Command repelled the KPA northwards past the 38th parallel; the ROK Army crossed after them, into North Korea. MacArthur made a statement demanding the KPA's unconditional surrender. Six days later, on 7 October, with UN authorization, the UN Command forces followed the ROK forces northwards. The X Corps landed at Wonsan (in southeastern North Korea) and Riwon (in northeastern North Korea), already captured by ROK forces. The Eighth U.S. Army and the ROK Army drove up western Korea and captured Pyongyang city, the North Korean capital, on 19 October 1950. The 187th Airborne Regimental Combat Team ("Rakkasans") made their first of two combat jumps during the Korean War on 20 October 1950 at Sunchon and Sukchon. The missions of the 187th were to cut the road north going to China, preventing North Korean leaders from escaping from Pyongyang; and to rescue American prisoners of war. At month's end, UN forces held 135,000 KPA prisoners of war. As they neared the Sino-Korean border, the UN forces in the west were divided from those in the east by 50–100 miles of mountainous terrain.
title: United States in the Korean War
paragraph_text: In response to North Korea's invasion into South Korea the United Nations convened to formulate a response. The U.N. demanded North Korea's immediate withdrawal and, when this was not met, United States Army General Douglas MacArthur was appointed supreme commander of U.N. forces. To halt the rapid progress of North Korean forces into the south Task Force Smith was deployed to the Korean front from Japan. Task Force Smith consisted of U.S. Army officers and regiments of the Army's 24th Infantry Division that were stationed in Japan as occupational forces. Unfortunately the 24th were under trained, poorly supplied, and outnumbered. The 24th offered very little resistance against the North Korean advance. American and South Korean troops were pushed south and in late July 1950 Task Force Smith was overrun in the city of Taejon. Troops from the Army's 25th Infantry Division were deployed to Taejon to establish a new line and pullout the decimated 24th I.D. This addition of combat troops did not stop the North Korean advance and both American and South Korean troops were pushed further south.
title: Ko Yong-hui
paragraph_text: Ko Yong-hui (; 26 June 1952 – 13 August 2004), also spelled Ko Young-hee, was the North Korean supreme leader Kim Jong-il's consort and the mother of North Korea's current leader, Kim Jong-un. Within North Korea she is only referred to by titles, such as "The Respected Mother who is the Most Faithful and Loyal 'Subject' to the Dear Leader Comrade Supreme Commander", "The Mother of Pyongyang", and "The Mother of Great Songun Korea."
title: Korean War
paragraph_text: On 7 June 1950, Kim Il - sung called for a Korea - wide election on 5 -- 8 August 1950 and a consultative conference in Haeju on 15 -- 17 June 1950. On 11 June, the North sent three diplomats to the South as a peace overture that Rhee rejected outright. On 21 June, Kim Il - Sung revised his war plan to involve a general attack across the 38th parallel, rather than a limited operation in the Ongjin peninsula. Kim was concerned that South Korean agents learned about the plans and South Korean forces were strengthening their defenses. Stalin agreed to this change of plan.

Question: Who led North Korea in to the war where UN troops approached the Yalu river.

Question decomposition:
question: when did un troops approach the yalu river
answer: During the Korean War
question: who lead north korea in #1
answer: Kim Il - Sung

Answer: Kim Il - Sung
Answer aliases: Kim Il-sung