On 4 September the estimate remained about the same [as 8/28] except that the enemy force in the Inch'ŏn landing area was placed at 1,800-2,500 troops because of an anticipated build-up there. This estimate remained relatively unchanged four days later, and thereafter held constant until the landing. [25-32]
American intelligence considered the enemy's ability to reinforce quickly the Inch'ŏn-Sŏul area as inconsequential. It held the view that only small rear area garrisons, line of communications units, and newly formed, poorly trained groups were scattered throughout Korea back of the combat zone around the Pusan Perimeter. Aerial reconnaissance reported heavy movement of enemy southbound traffic from the Manchurian border, but it was not clear whether this was of supplies or troops, or both. Although reports showed that the Chinese Communist Forces had increased in strength along the Manchurian border, there was no confirmation of rumors that some of them had moved into North Korea. [25-33]
The Far East Command considered the possibility that the enemy might reinforce the Inch'ŏn-Sŏul area from forces committed against Eighth Army in the south. If this were attempted, it appeared that the North Korean 3d, 13th, and 10th Divisions, deployed on either side of the main Sŏul-Taejon-Taegu highway, could most rapidly reach the Inch'ŏn area.