Lt. Cdr. Arlie G. Capps, gunnery officer on the amphibious staff to Admiral Doyle, appraised Inchon as a suitable target for amphibious assault as follows:
"We drew up a list of every natural and geographic handicap -- and Inchon had 'em all."
Probably the most dangerous disadvantages were the 32-foot tidal range, the eminent minability of the muddy shallow waters, and the enemy capability of trapping shipping in the upper harbor and blocking shipping in the lower harbor by sinking a single ship in the narrow channel.
To this was added the unsuitability of the assault beaches, and their dominance by the island of Wolmi-Do, which absolutely had to be taken and held for any hope of an amphibious assault to succeed, although tidal mud flats would isolate it from support for long periods each day.
The advantages were that Inchon was the closest landing site to Seoul, 25 miles inland across the Han river. Seoul was the capitol and communications center of South Korea. In addition, Korea's best airport, Kimpo, was only 16 miles away, on the road to Seoul. Our famous 1st Marine Division had no doubt that they would effect this landing, and travel that road, no matter what force the enemy might bring against them.
The Invasion "Beaches" themselves were:
A. Green Beach: A 200-yard strip on the northwest shore of Wolmi-Do, "Rocks with patches of sand, backed by a low-revetment and a ridge."
B. Red Beach: 220 yards of seawall, running north from the mainland root of the causeway joining Inchon to Wolmi-Do; immediately inland is a dismal industrial area with a tangle of railroad yards, a tank farm and a grimey Japanese-baroque brewery. At low tide, Red Beach's 1,000-yard mud flats have the crust and gooey consistency of badly-sanitized sludge at a sewage disposal plant.
C. Blue Beach: Four miles south-east of Red Beach, with a 14' seawall, backed by salt pans or eroded terraced hillock, approached over 4500 yards of mud flats.
When underwater gradients were considered, a tidal height of 23' was required for our LCVPs and 29' by LSTs. These tidal heights prevailed only once a month, and then only for three or four days. General MacArthur's concept was brilliant, but even more so were the organization, skill and resolution of our Naval and Marine Corps forces which implemented that concept.