movement behind KPA lines, and preferred Incheon, over Chumunjin-up or Kunsan as the landing site. He had originally envisioned such a landing, code-named Operation Bluehearts, for 22 July, with the US Army's 1st Cavalry Division landing at Incheon. However, by 10 July the plan was abandoned as it was clear the 1st Cavalry Division would be needed on the Pusan Perimeter. On 23 July, MacArthur formulated a new plan, code-named Operation Chromite, calling for an amphibious assault by the US Army's 2nd Infantry Division and the United States Marine Corps (USMC)'s 5th Marine Regiment in mid-September 1950. This, too fell through as both units were moved to the Pusan Perimeter. MacArthur decided instead to use the US Army's 7th Infantry Division, his last reserve unit in East Asia, to conduct the operation as soon as it could be raised to wartime strength. In preparation for the invasion, MacArthur activated the US Army's X Corps to act as the command for the landing forces, and appointed Major General Edward Almond, his chief of staff, as Corps' commander, anticipating the operation would mean a quick end to the war. Throughout August, MacArthur faced the challenge of re-equipping the 7th Infantry Division as it had sent 9,000 of its men to reinforce the Pusan Perimeter and was far understrength. He also faced the challenge that the USMC, reduced in size following World War II, had to rebuild the 1st Marine Division, using elements of the 1st Provisional Marine Brigade fighting at Pusan as well as the 1st Marine Regiment and the 7th Marine Regiment, which pulled US Marines from as far away as the Mediterranean Sea to Korea for the task. MacArthur ordered Korean Augmentation To the United States Army (KATUSA) troops, ROK conscripts assigned to US Army units, to reinforce the 7th Infantry Division, while allocating all equipment coming into Korea to X Corps, despite it being crucially needed by the US Army's Eighth Army on the Pusan Perimeter. MacArthur decided to use the Joint Strategic and Operations Group (JSPOG) of his United States Far East Command (FECOM). The initial plan was met with skepticism by the other generals because Incheon's natural and artificial defenses were formidable. The approaches to Incheon were two restricted passages, which could be easily blocked by naval mines. The current of the channels was also dangerously quick——and tides were so extreme as to prevent immediate follow-on landings.