The Second Phase Campaign of the Korean War was an extended military offensive by the Chinese People's Volunteer Army during the last week of November, 1950, and the first two weeks of December.
 The two major engagements were battles near the Ch'ongch'on River in the Chinese-designated Western Sector and Chosin Reservoir in their Eastern Sector.
 The Chinese opposed United Nations-authorized forces composed of American military and various allied forces.
The Battle of the Ch'ongch'on River, also known as the Battle of the Ch'ongch'on () or the Second Phase Campaign Western Sector (), was a decisive battle in the Korean War, and it took place from November 25 to December 2, 1950, along the Ch'ongch'on River Valley in the northwestern part of North Korea.
 In response to the successful Chinese First Phase Campaign against the United Nations forces, General Douglas MacArthur launched the Home-by-Christmas Offensive to evict the Chinese forces from Korea and to end the war.
 Anticipating this reaction, the Chinese People's Volunteer Army Commander Peng Dehuai planned a counteroffensive, dubbed the "Second Phase Campaign", against the advancing UN forces.
The Battle of Yongju (21–22 October 1950), also known as the Battle of the Apple Orchard, took place as part of the United Nations (UN) offensive towards the Yalu River, against the North Korean forces which had invaded South Korea during the Korean War.
 The battle was fought between the 27th British Commonwealth Brigade and the North Korean 239th Regiment which was encircled east of Yongju, where it was attacking the US 187th Airborne Regimental Combat Team (US 187 RCT).
 On 20 October US 187 RCT had parachuted ahead of the advancing UN spearheads into drop zones in Sukchon and Sunchon, 40 km north of the capital Pyongyang, with the objectives of cutting off the retreating North Korean forces that were withdrawing up the west coast of the Korean Peninsula and releasing American and South Korean prisoners of war.
 Although the airborne drop itself was a success, the operation came too late to intercept any significant North Korean elements and the American landings initially met little resistance.
 However, on 21 October as US 187 RCT began to advance south to the clear the Sukchon to Yongju road towards Pyongyang the Americans came under heavy attack from the North Korean 239th Regiment, and requested assistance.
The Battle of Unsan (Hangul: 운산전투 ; Hanja: 雲山戰鬪 ; RR: "Unsan jeontu "; MR: "Unsan chŏnt'u " ), also known as the Battle of Yunshan (), was a series of engagements of the Korean War that took place from 25 October to 4 November 1950 near Unsan, North Pyongan province in present-day North Korea.
 As part of the Chinese First Phase Campaign, the People's Republic of China's People's Volunteer Army made repeated attacks against the Republic of Korea 1st Infantry Division near Unsan beginning on 25 October, in an attempt to take advancing United Nations forces by surprise.
 In an accidental first encounter with the United States military during the Korean War, the Chinese 39th Corps attacked the unprepared US 8th Cavalry Regiment in Unsan on 1 November, resulting in one of the most devastating US losses of the Korean War.
The Battle of Wawon (Turkish: "Kunuri Muharebeleri" ), also known as the Battle of Wayuan (), was a series of delay actions of the Korean War that took place from November 27–29, 1950 near Wawon in present-day North Korea.
 After the collapse of the US Eighth Army's right flank during the Battle of the Ch'ongch'on River, the Chinese 38th Corps advanced rapidly towards the critical road junction at Kunu-ri in an effort to cut off United Nations forces' retreat route.
 In what was considered to be Turkey's first real combat action since the aftermath of World War I, the Turkish Brigade attempted to delay the Chinese advances at Wawon.
 Although during the battle the Turkish Brigade was crippled after being encircled by Chinese forces with superior numbers, they were still be able to breach the Chinese trap and rejoin the US 2nd Infantry Division.
The Eighth Army Ranger Company, also known as the 8213th Army Unit, was a Ranger light infantry company of the United States Army that was active during the Korean War.
 As a small special forces unit, it specialized in irregular warfare.
 Intended to combat the North Korean (NK) commandos who had been effective at infiltration and disruption behind United Nations (UN) lines, the Eighth Army Ranger Company was formed at the height of the Battle of Pusan Perimeter in September 1950 and was the first U.S. Army Ranger unit created since World War II.
 The company went into action as a part of the 25th Infantry Division during the UN advance into North Korea in October and November.
 It was best known for its defense of Hill 205 against an overwhelming Chinese attack during the Battle of the Ch'ongch'on River which resulted 41 of the 51 Rangers becoming casualties.
The Third Battle of Seoul, also known as the Chinese New Year's Offensive, the January–Fourth Retreat (Korean: 1•4 후퇴 ) or the Third Phase Campaign Western Sector (), was a battle of the Korean War, which took place from December 31, 1950 to January 7, 1951 around the South Korean capital of Seoul.
 In the aftermath of the major Chinese victory at the Battle of the Ch'ongch'on River, the United Nations Command started to contemplate the possibility of evacuation from the Korean Peninsula.
 Upon learning of this development, China's Chairman Mao Zedong ordered the Chinese People's Volunteer Army to cross the 38th parallel in an effort to pressure the United Nations forces to withdraw from South Korea.
The Battle of Kujin (25–26 October 1950), also known as the Battle of the Broken Bridge, took place during the United Nations (UN) offensive towards the Yalu River, which followed the North Korean invasion of South Korea at the start of the Korean War.
 The battle was fought between Australian forces from 3rd Battalion, Royal Australian Regiment (3 RAR) and elements of the 17th Tank Brigade of the Korean People's Army over a key bridge across the Taeryong River near Kujin, North Korea.
 On 25 October the 27th British Commonwealth Brigade had resumed their advance towards Pakchon after crossing the Chongchon River, with 3 RAR as the lead battalion.
 Arriving at Kujin, the Australians discovered that the centre span of the 300 m concrete bridge had been demolished by North Korean engineers, blocking their passage across the river.
 A platoon-sized reconnaissance patrol crossed the river using debris from the destroyed span; however, it was soon forced to withdraw by North Koreans holding the high ground.
 Airstrikes and artillery fire were subsequently called-in at 17:15 by the Australians as they prepared to conduct an assault.
The Korean War (in South Korean Hangul: 한국전쟁 ; Hanja: 韓國戰爭 ; RR: "Hanguk Jeonjaeng " , "Korean War"; in North Korean Chosŏn'gŭl: 조국해방전쟁 ; Hancha: 祖國解放戰爭 ; MR: "Choguk haebang chǒnjaeng " , "Fatherland Liberation War"; 25 June 1950 – 27 July 1953) was a war between North Korea (with the support of China and the Soviet Union) and South Korea (with the principal support of the United States).
 The war began on 25 June 1950 when North Korea invaded South Korea.
 The United Nations, with the United States as the principal force, came to the aid of South Korea.
 China came to the aid of North Korea, and the Soviet Union also gave some assistance to the North.
The Battle of Chipyong-ni (French: "Bataille de Chipyong-ni" ), also known as the Battle of Dipingli (), was a decisive battle of the Korean War, that took place from 13–15 February 1951 between American and French units of the US 23rd Infantry Regiment and various units of the Chinese People's Volunteer Army (PVA) around the village of Chipyong-ni, present-day Jipyeong-ri.
 The result was a United Nations Command victory.
 The battle, along with the Third Battle of Wonju, has been called "the Gettysburg of the Korean War," and represents the "high-water mark" of the Chinese incursion into Korea.
 Due to the ferocity of the Chinese attack and the heroism of the defenders, the battle has also been called, "...one of the greatest regimental defense actions in military history."

Question: The Battle of the Ch'ongch'on River and Korean War took place in what year?
Answer: 1950