It was in Osan in July Juche 39 (1950) that the advancing Korean People's Army encountered the U.S. forces for the first time during the war.

At that time the U.S. forces hurled into the Korean front its 24th Infantry Division, claiming that their involvement in the war would turn the front situation in favor of them at once.

Commander of the Division Dean, dispatched the "Smith commandos", comprised of the 1st Battalion of the 21st Regiment and the 52nd Artillery Battalion, as an advance party of the Division to the area of Osan in a bid to block the KPA units' advance into the south. Smith, head of the "commandos", asserted that its appearance in the front would frighten the KPA soldiers off.

After all, a KPA unit encountered the "Smith commandos" in Osan. The KPA soldiers bravely rushed into the enemy's positions, destroying its artillery pieces and mercilessly attacking the enemy troops. This battle ended in total destruction of the "commandos" in less than two hours.

The first defeat of the GIs in Osan area struck the U.S. military bosses with horror.