OP 100-B



On 12 August, MacArthur issued CINCFE Operation Plan 100-B and specifically named the Inch'ŏn-Sŏul area as the target that a special invasion force would seize by amphibious assault. [25-6]


Published on 12 August as CinCFE Operation Plan No. 100B, it was based on these assumptions:

  1. (a) that the North Korean ground advance would be stopped in time to permit the build-up of our forces in South Korea;
  2. (b) that our forces in South Korea would be built up to the capability of mounting effective offensive operations against NKPA forces opposing them;
  3. (c) that we retain air and naval supremacy in the area of operation;
  4. (d) that the NKPA ground forces would not receive major reinforcements from the USSR or Red China;
  5. (e) that there would be no major change in the basic disposition of the NKPA forces.[9]