Operations Plan 5027 (OPLAN 5027) are a series of military operations plans made by the United States and South Korea for the defense against a possible North Korean invasion. History Before 1973, OPLAN 5027 was primarily focused on defeating a North Korean invasion, with a 50-mile retreat from the penetrated Demilitarized Zone to positions south of the Han River (known as the Hollingsworth Line). Allied forces would then wait for American and allied reinforcements before counterattacking. With the withdrawal of the United States from Vietnam and concerns of North Korea doubting America's commitment to defend South Korea, Combined Forces Commander US General James F. Hollingsworth developed a forward-based offensive strategy known as OPLAN 5027-74. The new plans called for most artillery, tanks, and infantry to be moved toward the Military Control Zone five miles south of the Demilitarized Zone. Offensive strategies following the defeat of invasion forces included two brigades of the US 2nd Division to seize the nearby city of Kaesong, around-the-clock B-52 bomber raids, and a "violent, short war" to capture the capital city of Pyongyang. No mention was made of the use of tactical nuclear weapons in case of overwhelming North Korean forces, though the Congressional Budget Office predicted that without their use, the new strategy could result in the initial loss of Seoul. A variant of the operation plan, OPLAN 5027-94, was reportedly under consideration by CINCPAC in 1994 for a scenario where South Korean forces could halt a North Korean invasion and stabilize a defensive line at FEBA Bravo, twenty to thirty miles from the DMZ. With the arrival of American and allied reinforcements, a major air campaign would be waged against North Korea before a land offensive by a US Marine Expeditionary Force (in division strength), the 82nd Airborne Division, and South Korean divisions towards Wonsan. A combined US-ROK force would also stage an amphibious landing near Wonsan, with the two forces joining together for an advance on Pyongyang. The scenario depended on South Korean forces holding out against a North Korean advance for an initial 5–15 days, as well as potentially another 15–20 days during preparations for the counteroffensive. Following concerns over a North Korean nuclear program, OPLAN 5027 was completely overhauled with OPLAN 5027-96, which included a new agreement with the Japanese government for the use of Japanese bases in the event of a war. Further revisions and more detailed offensive strategies