Intelligence Bulletin Vol 02 No 07 March 1944 and Vol 02 No 08 April 1944

The following information about the Japanese defense of Betio Island is based on a joint study made by Marine Corps, Army, and Navy intelligence personnel.1 The fundamental points brought out by this study are presented in the Intelligence Bulletin so that they may be widely disseminated, particularly among junior officers and enlisted men of the Army.

That the Japanese organized their Betio defenses for an all-around, decisive struggle to keep United States forces from reaching the beaches is borne out by a study of the map on pages 34 and 35. This map, drawn to scale, is designed to show an over-all picture of the enemy defensive setup. The insets show important areas in detail.

The Japanese beach defenses consisted of wellemplaced and well-sited weapons, various types of obstacles, and mines. The weapons included grenades, JA short preliminary discussion of the Japanese defense of Betio Island was carried in Intelligence Bulletin, Vol. II, No. 6, pp. 19-38.

mortars, rifles, light and heavy machine guns, 13-mm dual-purpose machine guns, 37-mm guns, 70-mm infantry guns, 75-mm mountain guns (Model 41), 75-mm dual-purpose guns (Model 88), 80-mm antiboat guns, 127-mm twin-mount, dual-purpose guns, 140-mm coast-defense guns, and 8-inch coast-defense guns.

The obstacles included pyramid-shaped, reinforced concrete obstacles, which were placed about halfway around the island on the coral reef; an antiboat barricade, made of coconut-palm logs; double-apron barbed wire; a perimeter barricade, constructed chiefly of coconut-palm logs; and antitank ditches, dug a short distance back of the perimeter barricade.

Antipersonnel and antiboat mines were laid on the fringing reef — frequently between the concrete obstacles — and on the beaches.

Several Japanese flame throwers, were found.

Appropriate fire-control equipment was installed for the coast-defense and antiaircraft batteries, including range finders, directors, and searchlights. The weapons, as a rule, were mounted in strongly constructed emplacements made of coconut-palm logs, reinforced concrete, and revetted sand.

The Japanese employed the 13-mm (approximately.50 caliber) machine gun as their basic beach-defense weapon along the entire north coast and on both sides of the eastern tip. Along the western and southwestern coasts, the 7.7-mm heavy machine gun was the basic weapon.

The organization for defense inshore was haphazard. Beaten on the beaches, the Japanese fell back to bombproof ammunition, shelters and personnel shelters inshore from the beaches, and fired from the doors of the shelters. These were blind to attack from several directions; they were not designed as blockhouses, and had only a few firing ports.

Contents
Part One:: JapanSection I: Defense op Betio IslandSection II: How Japanese Depended Hilly Jungle CountryPart Two:: GermanySection I: Military Leadership, as the Germans See ItSection IV: Some Notes on German Mountain WarfarePart One:: JapanSection I: Defense of Betio Island
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