When North Korea invaded South Korea in the summer of 1950 the United States military was not ready to rapidly deploy major and modern forces to the Korean Peninsula. The global U.S. military strategy to contain the Soviet Union, and Communist China, was based on nuclear war fighting and a belief that major ground wars were now an obsolete form of warfare; until North Korea invaded. Initially, the U.S. put together a Marine Provisional Brigade and sent Army units stationed in Japan to South Korea to stem the tide until major land, sea and air units could be deployed. U.S. infantry – Army and Marines – used the same weapons as during World War II, including the M-1 Rifle, the Browning Automatic Rifle, the famous .45 caliber pistol and the M2 .50 caliber heavy machine gun. The artillery and mortars were the standard the standard US artillery of WWII, the 105mm, the 155mm, the 8-in howitzer. The M4A3 ‘Sherman IV’, the WWII workhorse fitted with a new high-velocity 76.2mm gun, became the principle US battle tank during the Korean War. Armor tactics were a challenge given the mountainous terrain and topography of Korea and tanks were used primarily as artillery support for infantry rather than as independent, maneuvering offensive formations.