Question: When did the stalemate happen in the war where UN troops approached the Yalu River?

title: Rock Island Railroad Bridge (Columbia River)
text: The Rock Island Railroad Bridge is BNSF Railway's bridge across the Columbia River, at Rock Island, Washington. The structure consists of one through truss, one deck truss, and an approach trestle.

title: DUKW
text: Designed by a partnership under military auspices of Sparkman & Stephens and General Motors Corporation (GMC), the DUKW was used for the transportation of goods and troops over land and water. Excelling at approaching and crossing beaches in amphibious warfare attacks, it was intended only to last long enough to meet the demands of combat. Surviving DUKWs have since found popularity as tourist craft in marine environments.

title: Chunggang County
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: Usi County
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: First Battle of Panipat
text: When Ibrahim's army arrived, he found the approach to Babur's army too narrow to attack. While Ibrahim redeployed his forces to allow for the narrower front, Babur quickly took advantage of the situation to flank (tulghuma) the Lodi army. Many of Ibrahim's troops were unable to get into action, and fled when the battle turned against Ibrahim. Faced with musket fire, cannon fire and cavalry attacks from all sides, Ibrahim Lodi fought and died with 6,000 of his remaining troops.

title: Pope Paul VI
text: Pope Paul VI became the first reigning pontiff ever to visit the Americas when he flew to New York in October 1965 to address the United Nations. As a gesture of goodwill, the pope gave to the UN two pieces of papal jewelry, a diamond cross and ring, with the hopes that the proceeds from their sale at auction would contribute to the UN's efforts to end human suffering. During the pope's visit, as the U.S. involvement in the Vietnam War escalated under President Johnson, Paul VI pleaded for peace before the UN:

title: Siege of Ninety-Six
text: The Siege of Ninety Six was a siege in western South Carolina late in the American Revolutionary War. From May 22 to June 18, 1781, Continental Army Major General Nathanael Greene led 1,000 troops in a siege against the 550 Loyalists in the fortified village of Ninety Six, South Carolina. The 28-day siege centered on an earthen fortification known as Star Fort. Despite having more troops, Greene was unsuccessful in taking the town, and was forced to lift the siege when Lord Rawdon approached from Charleston with British troops.

title: Namibia
text: South West Africa became known as Namibia by the UN when the General Assembly changed the territory's name by Resolution 2372 (XXII) of 12 June 1968. In 1978 the UN Security Council passed UN Resolution 435 which planned a transition toward independence for Namibia. Attempts to persuade South Africa to agree to the plan's implementation were not successful until 1988 when the transition to independence finally started under a diplomatic agreement between South Africa, Angola and Cuba, with the USSR and the USA as observers, under which South Africa agreed to withdraw and demobilise its forces in Namibia. As a result, Cuba agreed to pull back its troops in southern Angola sent to support the MPLA in its war for control of Angola with UNITA.

title: Al-Qubeir massacre
text: The Al-Qubeir massacre (), also known as the Hama massacre, occurred in the small village of Al-Qubeir near Hama, Syria, on 6 June 2012 during the country's ongoing civil conflict. Al-Qubeir is described as a Sunni farming settlement surrounded by Alawite villages in the central province of Hama. According to preliminary evidence, troops had surrounded the village which was followed by pro-government Shabiha militia entering the village and killing civilians with "barbarity," UN Secretary-General Ban Ki-moon told the UN Security Council.

title: Trench warfare
text: Trench warfare is a type of land warfare using occupied fighting lines consisting largely of military trenches, in which troops are well - protected from the enemy's small arms fire and are substantially sheltered from artillery. The most famous use of trench warfare is the Western Front in World War I. It has become a byword for stalemate, attrition, sieges and futility in conflict.

title: Linjiang Yalu River Bridge
text: Linjiang Yalu River Bridge: 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
text: With Lieutenant-General Matthew Ridgway assuming the command of the U.S. Eighth Army on 26 December, the PVA and the KPA launched their Third Phase Offensive (also known as the "Chinese New Year's Offensive") on New Year's Eve of 1950. Utilizing night attacks in which UN Command fighting positions were encircled and then assaulted by numerically superior troops who had the element of surprise, the attacks were accompanied by loud trumpets and gongs, which fulfilled the double purpose of facilitating tactical communication and mentally disorienting the enemy. UN forces initially had no familiarity with this tactic, and as a result some soldiers panicked, abandoning their weapons and retreating to the south. The Chinese New Year's Offensive overwhelmed UN forces, allowing the PVA and KPA to conquer Seoul for the second time on 4 January 1951.

title: Korean War
text: After these reversals of fortune, which saw Seoul change hands four times, the last two years of fighting 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: Schwartzkopff torpedo
text: During the First Sino-Japanese War (1894–1895), both the Chinese and Japanese navies were equipped with Schwartzkopff torpedoes. The Chinese Navy had the first opportunity to employ their torpedoes during the Battle of Yalu River, but none were able to hit their targets. This poor performance was attributed to improper maintenance of the weapons by the Chinese. Five months later, during the Battle of Weihaiwei, the Japanese sent torpedo boats to attack the Chinese fleet. Firing eleven Schwartzkopff torpedoes, the Japanese managed to sink three Chinese warships. It was the most successful deployment of torpedoes at that point in history.

title: Eritrea
text: Disagreements following the war have resulted in stalemate punctuated by periods of elevated tension and renewed threats of war. The stalemate led the President of Eritrea to urge the UN to take action on Ethiopia with the Eleven Letters penned by the President to the United Nations Security Council. The situation has been further escalated by the continued efforts of the Eritrean and Ethiopian leaders in supporting opposition in one another's countries.[citation needed] In 2011, Ethiopia accused Eritrea of planting bombs at an African Union summit in Addis Ababa, which was later supported by a UN report. Eritrea denied the claims.

title: Korean War
text: For the remainder of the Korean War the UN Command and the PVA fought, but exchanged little territory; the stalemate held. Large - scale bombing of North Korea continued, and protracted armistice negotiations began 10 July 1951 at Kaesong. On the Chinese side, Zhou Enlai directed peace talks, and Li Kenong and Qiao Guanghua headed the negotiation team. Combat continued while the belligerents negotiated; the UN Command forces' goal was to recapture all of South Korea and to avoid losing territory. The PVA and the KPA attempted similar operations, and later effected military and psychological operations in order to test the UN Command's resolve to continue the war.

title: Korean War
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
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
text: The Chinese counterattacked in April 1951, with the Fifth Phase Offensive, also known as the Chinese Spring Offensive, with three field armies (approximately 700,000 men). The offensive's first thrust fell upon I Corps, which fiercely resisted in the Battle of the Imjin River (22–25 April 1951) and the Battle of Kapyong (22–25 April 1951), blunting the impetus of the offensive, which was halted at the "No-name Line" north of Seoul. On 15 May 1951, the Chinese commenced the second impulse of the Spring Offensive and attacked the ROK Army and the U.S. X Corps in the east at the Soyang River. After initial success, they were halted by 20 May. At month's end, the U.S. Eighth Army counterattacked and regained "Line Kansas", just north of the 38th parallel. The UN's "Line Kansas" halt and subsequent offensive action stand-down began the stalemate that lasted until the armistice of 1953.

title: Yalu River
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.

Answer: began 10 July 1951