This is a reproduction of the official Japanese map of their installations on Roi & Namur Islands in the Marshall Islands during WWII. Roi on the left, Namur on the right. The original was found in one of the Japanese Command offices on Namur Island during the fighting. Prior to fighting our way to the beach, each Marine was given a copy of this or another map to acquaint us with the lay of the enemy facilities with instructions to destroy the maps before encountering the enemy. Officers and other leaders naturally had copies for directing the invasion. As evident, I chose to keep mine. This copy has hung on the wall of my office for years.
The English translations on it were done by a linguist member of the Intelligence Section of the 4th Marine Division, 2nd Lt. D. (Donald) E. Redlin, USMCR.
Roi and Namur Islands are connected by a causeway (man-made) and a land contact on the South. The 23rd Regiment (mine) was assigned to invade and conquer Roi; the Japanese heavy bomber base that was the real military target in the Marshall Islands. Namur was assigned to either the 24th or 25th regiment.
Namur was the Command Center that housed the personnel for its air patrol activities, its defensive artillery, and infantry. It was tree covered and possessed excellent camouflage of its defensive artillery, customary infantry defensive emplacements, fuel storage and ammunitions dumps and the other logistical needs for housing thousands of personnel, airplane technicians and infantry units.
Roi was one huge runway system that had large hangars for maintaining its air facilities and storage areas for aircraft. The map shows how large the runways actually were, with various directional capabilities (for landing and takeoff runways to accommodate wind patterns). The runways were honeycombed also tunnels under much of the heavy concrete runway surfaces for servicing aircraft and movement of troops undetected from the air. Its surfaces were pockmarked from Navy ships shelling and aircraft bombing prior to our landing, making it impossible for incoming and outgoing Japanese air traffic.
The 23rd quickly advanced well into the island without frontal contact with the enemy troops who came through their tunnels, surfaced to our rear through breaks in the concrete to fire at us from behind our line of advance. We adjusted to the Japanese actions from every direction, not only to the front. Flame throwers, grenades, and satchel charges, together with rifle and machine gun fire, enabled our advance to continue on to victory.