- 1931-1932: Mostly of their own volition, Japan's Kwantung Army occupies Chinese Manchuria and sets up a puppet state of "Manchuko". America wants to return Manchuria to the Chinese; this is one reason behind Pacific fighting in World War II.
- 1937: Japan declares war on China.
- February 1945: Roosevelt, Churchill and Stalin meet at Yalta.
- July 1945: Roosevelt dies, succeeded by Truman, who represents the US at Potsdam. Truman "gets tough" on communism; Stalin grabs territory.
- August 10, 1945: After atomic bombs are dropped on Hiroshima and Nagasaki, the Japanese offer surrender in World War II. Russian troops enter Korea.
- August 28, 1945: After reaching the 38th Parallel of Korea, Russian troops stop.
- October 20, 1945: Syngman Rhee makes first public appearance in South Korea after years of exile.
- Summer 1947: Marshall Plan announced.
- September 1947: Congress/JCS (Joint Chiefs of Staff) want to get out of Korea.
- September 1947: Cominform (Communist Information Bureau) founded in Soviet Union.
- November 14, 1947: UN passes American resolution calling for free elections in Korea.
- May 10, 1948: Korean Election Day.
- June 24, 1948: Berlin Blockade
- September 9, 1948: In North Korea, Democratic People's Republic of Korea (PRK) proclaimed.
- January 12, 1949: Dean Acheson speech to National Press Club Says South Korea not a vital part of US defense perimeter in Asia.
- January 19, 1949: Korean Aid Bill fails to pass the House of Representatives.
- April 4, 1949: NATO Pact signed
- September 1949: "Joe One"; Soviets test their first A-bomb--the arms race begins.
- October 2, 1949: Mao Zedong proclaims PRC (People's Republic of China).
- January 14, 1950: Ho Chi Minh proclaims DRV (Democratic Republic of Vietnam).
- April 25, 1950: Truman approves NSC-68
- May 30, 1950: In South Korea, Republic Of Korea elections. Many conservatives ousted by moderates.
- June 25, 1950: North Korea crosses the 38th Parallel, invading South Korea.
- June 25, 1950: First Blair House meeting.
- June 26, 1950: North Korea's tanks reach the outskirts of Seoul.
- June 27, 1950: Truman commits US Naval and Air support to South Korea.
- June 27, 1950: American Delegate asks UN to furnish assistance to ROK (Republic of Korea) to restore international peace.
- June 29, 1950: General MacArthur flies to South Korean headquarters at Suwon.
- June 30, 1950: Truman and advisers agree to give MacArthur 2 divisions.
- July 2, 1950: NKPA (North Korean People's Army) takes Suwon.
- July 22, 1950: Communist Chinese attack Nationalist Chinese islands, Quemoy and Little Quemoy.
- July 29, 1950: MacArthur visits Formosa, home of the Nationalist Chinese defeated by Mao.
- August 17, 1950: US announces in UN its goal of a unified, anti-Communist Korea.
- August 27, 1950: US planes accidentally attack Manchurian airfields.
- September 11, 1950: Truman approves NSC-81/1.
- September 15, 1950: With US/UN/ROK forces pushed back nearly to the end of the Korean peninsula, MacArthur launches the Inchon Invasion.
- September 27, 1950: Walker's Eighth Army makes contact with X Corps. MacArthur gives OK for US forces to cross the 38th Parallel.
- September 29, 1950: Syngman Rhee's government ceremonially restored in reconquered Seoul.
- October 9, 1950: US Army crosses 38TH Parallel near Kaesong.
- October 15, 1950: Wake Island Meeting
- October 19, 1950: US forces occupy Pyongyang
- October 24, 1950: MacArthur orders his troops into Korea's northernmost provinces.
- October 25, 1950: South Korean ROK forces annihilated by PRC (People's Republic of China) forces at Pukchin.
- November 1, 1950: First US vs. Communist Chinese fighting at Unsan
- November 3, 1950: UN resolution passed, censuring North Korea for "breach of peace"
- November 7, 1950: Congressional Elections in US, seen as a referendum on Truman's policy.
- November 27, 1950: US Marines/Infantry surrounded by Chinese Communist forces at Chosin Reservoir.
- November 30, 1950: In press conference, Truman admits US may be considering using A-Bomb.
- December 15, 1950: Truman declares a state of national emergency.
- January 4, 1951: Ridgway evacuates Seoul, withdraws from Inchon
- January 25, 1951: Operation Thunderbolt. US/UN/ROK forces go back on the offensive.
- February 1, 1951: UN censures People's Republic of China for "aggression"
- February 1951: Operation Killer begun.
- March 7, 1951: Ridgway launches Operation Ripper.
- March 15, 1951: US/UN/ROK forces retake Seoul.
- March 24, 1951: MacArthur unilaterally issues an ultimatum to the People's Republic of China.
- April 4, 1951: Congress endorses NATO, sends Eisenhower to head unified NATO command.
- April 5, 1951: Operation Rugged.
- April 5, 1951: Truman dismisses MacArthur from command.
- May 3, 1951 to June 25, 1951: Senate Foreign Relations Committee investigates MacArthur's dismissal.
- April 14, 1951: Gen. James Van Fleet assumes tactical command of Eighth Army.
- April 22, 1951: All-out Communist offensive fails to retake Seoul.
- May 15, 1951: Another Communist offensive, again fails to take territory.
- May 18, 1951: Ridgway launches counteroffensive.
- May 18, 1951: UN nations start military goods boycott of the People Republic of China.
- May 30, 1951: Operation Piledriver, an offensive against the Iron Triangle, begins.
- June 30, 1951: Ridgway broadcasts first American overture for peace talks.
- July 8, 1951: Peace talks begin at Kaesong.
- August 19, 1951: Communists accuse UN forces of violating the Kaesong area, suspend the talks.
- October 25, 1951: Peace talks resume at Panmunjom.
- March 29, 1952: Truman announces he will not run for reelection.
- April 11, 1952: Truman relieves Eisenhower of command so he can run for President.
- June 1952: Washington authorizes bombing Korean power plants on the Yalu river.
- July 11, 1952: US air attack on Pyongyang.
- August 5, 1952: Rhee wins another clearly rigged election.
- November 4, 1952: Eisenhower wins Presidential election in landslide.
- November 29, 1952: Eisenhower secretly goes to Korea on fact-finding mission
- February 11, 1953: Eisenhower replaces the frustrated Van Fleet with Lt. Gen. Maxwell Taylor.
- April 16, 1953: Communists attack "Pork Chop Hill"
- April 26, 1953: Talks resume at Panmunjom.
- June 8, 1953: "Terms of Reference," regulating POW repatriation, signed.
- July 19, 1953: Delegates reach agreement at Panmunjom.
- July 27, 1953: Peace Treaty signed at Panmunjom. 38th parallel reset as boundary between communist North and anti-communist South. Cold War tensions continue unabated. Gen. Mark W. Clark says he has "the unenviable distinction of being the first US Army commander to sign an armistice without victory."