Battle of Osan 

US #3187e from the Celebrate the Century sheet.

On July 5, 1950, US forces had their first fight of the Korean War at the Battle of Osan.

On June 25, 1950, 75,000 North Korean soldiers poured across the 38th Parallel to begin their takeover of the South Korean peninsula.  Soviet tanks and heavy artillery supported them.  The South’s Republic of Korea (ROK) troops had no tanks or weapons to combat tank attacks.  Within days, they were pushed south and Seoul, the capital, fell to the northern forces.  ROK soldiers retreated or defected to the Northern army.

US #3187e – Mystic First Day Cover.

Fearing the invasion would advance the spread of communism worldwide, the United Nations Security Council condemned North Korea’s actions and called for a ceasefire.  On the 27th, the council decided to send UN forces to help the ROK defend itself.  In a speech supporting US involvement, President Truman said, “I felt certain that if South Korea was allowed to fall, Communist leaders would be emboldened to override nations closer to our shores.”

US #2152 was issued in 1985 to honor Korean War veterans.

The US committed the majority of forces in the UN command and led the operation.  America’s military had been greatly reduced after World War II because of budget cuts and an emphasis on funding research on nuclear bombs.  The military had to be strengthened and reorganized quickly to effectively fight a war.

US #2152 – Classic First Day Cover.

US forces stationed in Japan were the first to go to Korea.  The 21st Infantry Regiment of the 24th Infantry Division was considered the most combat-ready.  On June 30, a force of 400 poorly equipped and inexperienced American soldiers were transported from Japan to South Korea.  Named Task Force Smith, their mission was to establish a line of defense as far north as possible and slow the North Korean army so the other American divisions could be brought in to establish a stronger defensive line in the South.  On July 4, Lt. Col. Charles Smith established a one-mile-long line along the road to the north of Osan, near Seoul.

Item #59886 – Korean War Memorial Coin Cover.

The next morning, a column of North Korean tanks approached.  The US soldiers were dangerously ill-equipped, lacking anti-tank guns.  Instead, they had 2.35-inch rocket launchers and 57-mm recoilless rifles.  US artillery fire caused little damage, and most of the tanks continued on.  At 11:00 am more tanks were spotted, and a column of trucks carrying about 5,000 soldiers followed these.

Item #M12116 – Korean War Memorial silver proof coin.

Smith ordered his forces to fire with everything they had. Several trucks were destroyed, but the Northern infantry quickly formed and advanced on the Americans.  The task force held their lines for three hours but was forced to retreat because their ammunition was running low and they had lost communications. Though it was clearly a victory for the North, Task Force Smith slowed down the much larger force for seven hours.

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  1. A little more would have been in order here. for instance:

    Task Force Smith slowed down the much larger force for seven hours, thus ???? or what was the outcome of the action that slowed the advance of the North Koreans. Did it allow the ROK and US forces to build to an effective force and perhaps push the North back from Osan? you left a hanging chad on this one.

  2. I had no previous knowledge of the first U S military action in the Korean War. Thank you Mystic for the history lesson.

  3. I hope you guys at Mystic are thick skinned. It’s hard to believe that we have people complain about a free service. You guys and gals at Mystic are doing great, if someone needs additional information or needs to fact check something, we have a whole world wide web just begging people to explore. Again, and as always, thanks for the free history lessons everyday. I have learned a lot about history and stamps over the past five years. I hope you guys keep this free service.

  4. I am with Dennis on this one. I have learned so much history in the past couple of years through this daily service, and I am very appreciative. I owe you a debt of gratitude for the great job you guys do in giving us the broad strokes of history, even if the minute details get lost at times. Thanks so much!!

  5. A very heroic effort which did allow for regrouping. Thanks for reporting on the “Forgotten War” in which my dad was a highly decorated infantry major.

  6. I was in the Women’s Air Force during that time. They called it a Conflict. I and those there called it a war. Here we are again at the same place. Will our country ever learn I am 88 years old but I remember and believe that IF THEY HAD LET GENERAL MCARTHUR HAVE HIS WAY, WE WOULD NOT BE OVER THERE AGAIN. we COULD HAVE WITHSTOOD THE COUNTRY HELPING KOREA THEN. Will America ever learn??? ALL IN ALL, IT TAKES LEADERSHIP.. WHERE IS GENERAL POWELL AND GENERAL SWARTZCOFF(SPELLING.).???? We have been years in Afghanistan and are still there. I HOPE our country does not take on another war in Korea. God Bless all our men and women in the Armed Services.

  7. My husband served in the Korean War. He rearly talked about what had happened over there! It must have been a horrible time.

  8. Since you really did not want opinions of someone who lived at this time, I will post another one.

    NICE WAR, SORRY YOU MISSED IT./ ALL YOU SECOND HAND OPINION PEOPLE /WHO SEEM TO KNOW ABOUT EVERY SUBJECT / CAN HAVE THIS WEBSITE. Sorry I wasted your time. I did not realize you only wanted the opinions of the same people who have an opinion about everything which usually means they know very little. about anything.

    1. Hi Phyllis – Sorry for the delay in publishing your first comment on this article. Your comments are definitely welcome here. Thank you.

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