On June 27, US President Truman ordered US forces to South Korea.

109th Tank Regiment (Numbers 300 to 339).203rd Tank Regiment (Numbers 200 to 239).107th Tank Regiment (Numbers 100 to 139).Each tank regiment consisted of 3 battalions of 13 tanks (Battalion Commander’s tank and 3 companies of 4 tanks each.) The first digit of the tactical number indicated the Regiment and the following digits were numbered consecutively throughout the regiment. After the capture of Seoul, the NKPA 105th Armored Brigade was raised to division status. On 25 June 1950, the North Korean Peoples Army (NKPA) spearheaded by ex-Soviet T-34/85 tanks and SU-76M assault guns of the 105th Armored Brigade crossed the 38th Parallel and invaded South Korea. During the war, there were 15 tank-vs-tank actions that involved the 1st Marine Tank Battalion.

The battalion participated in the amphibious landing at Inchon, the liberation of South Korean capital Seoul and the amphibious landing at Wonsan where it advanced north supporting the Marines at the Chosin reservoir. Upon arrival, elements of the battalion disembarked at the port of Pusan and immediately went into combat where it was the first unit to engage and defeated the feared T-34 tank. Soon after the outbreak of the Korean War, the US 1st Marine Tank Battalion was one of the armored units ordered to prepare for a rapid deployment to Korea.

The korean war tank battles