Question: Which event took place first, Operation Undertone or The Battle of the Ch'ongch'on River?

Context paragraphs:
Glory By Honor XV: Glory By Honor XV was a two night, two city professional wrestling event produced by the U.S.-based wrestling promotion Ring of Honor.  The first night of the event took place on October 14, 2016 at the Frontier Fieldhouse in Chicago Ridge, Illinois.  The second part of the event took place on October 15, 2016 at Ford Community & Performing Arts Center in Dearborn, Michigan.

Battle of Wawon: 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.

Vancouver Island Shootout: The Vancouver Island Shootout was an annual curling bonspiel started in 2011 as part of the World Curling Tour.  For the 2011–12 curling season, the event took place at the Juan de Fuca Curling Club in Colwood, British Columbia.  The men's event was held in a triple knockout format, and the women's event was held in a round robin format.  For the 2012–13 curling season and 2014–15 curling season, the event took place at the Victoria Curling Centre in Victoria, British Columbia, and both the men's and women's events were held in a triple knockout format.

2010 Internazionali BNL d'Italia: The 2010 Internazionali BNL d'Italia was a tennis tournament, being played on outdoor clay courts at the Foro Italico in Rome, Italy.  It was the 67th edition of the event and was classified as an ATP World Tour Masters 1000 event on the 2010 ATP World Tour and a Premier 5 event on the 2010 WTA Tour.  The men's event took place from April 24 to May 2, 2010 while the women's event took place from April 30 to May 8, 2010.

Glory By Honor XIV: Glory By Honor XIV was a two night, two city professional wrestling event produced by the U.S.-based wrestling promotion Ring of Honor.  The first night of the event took place on October 23, 2015 at the Wing's Event Center in Kalamazoo, Michigan.  The second part of the event took place on October 24, 2015 at Montgomery County Fairgrounds Coliseum in Dayton, Ohio.

2014 Tianjin Health Industry Park: The 2014 Tianjin Health Industry Park was a professional tennis tournament played on clay courts.  It was the first edition of the tournament and part of the 2014 ATP Challenger Tour and 2014 ITF Women's Circuit, offering a total of $50,000+H (ATP) and $25,000 (ITF) in prize money.  It took place in Tianjin, China, the men's event took place from 16 to 22 June 2014 while the women's event took place from 19 to 25 May 2014.

Battle of the Ch'ongch'on River: 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.

EBSA European Under-21 Snooker Championships: The EBSA European Under-21 Snooker Championships is the premier non-professional junior snooker tournament in Europe.  The event series is sanctioned by the European Billiards & Snooker Association.  It took place first in 1997 and is held annually since then.  The event was known as the EBSA European Under-19 Snooker Championships until 2010.  In most years the winner of the tournament qualifies for the next two seasons of the World Snooker Tour and well as being awarded the Ebdon Trophy which is named in honour of former World Champion Peter Ebdon.

Third Battle of Seoul: 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.

Operation Undertone: Operation Undertone was a large assault by the U.S. Seventh and French 1st Armies of the U.S. Sixth Army Group as part of the Allied invasion of Germany in March 1945 during World War II.

Supporting paragraphs: Battle of the Ch'ongch'on River Operation Undertone
Answer: Operation Undertone