1. GENERAL

Japanese landing operations show that considerable thought and training have been devoted to the coordinated employment of the army, the navy, and the air arm in amphibious warfare. Task forces composed of units from such fighting arms have specially devised tactics and highly developed landing equipment. The latter includes both landing-craft carriers which disgorge fully loaded boats from their sterns and sides, and landing craft specially designed to negotiate shallow and weed-infested waters. Rubber assault boats and special equipment to aid the individual soldier, such as rubber belts which can be inflated, have also been used.

2. TASK FORCES

a. Organization

In recent operations the Japanese have used two types of joint task forces involving air, ground, and sea personnel and equipment—the divisional group and the brigade group. Their composition was as follows:

(1) Divisional group.—(a) From 70 to 92 shore-based aircraft consisting of 30 to 40 heavy bombers; 24 to 36 fighters; 8 flying boats; and from 40 to 100 carrier-borne planes;

(b) One division of troops (15,000);

(c) One battalion of parachute troops (1,600);

(d) From 32 to 46 vessels consisting of 2 aircraft carriers (each capable of carrying 40 to 60 planes); 6 cruisers (each of which carried 3 reconnaissance planes); 2 to 4 submarines; 10 to 14 destroyers; and 12 to 20 transports.

(2) Brigade group.—(a) From 48 to 58 shore-based aircraft consisting of 20 to 30 heavy bombers; 12 to 24 fighters; 8 flying boats; and 48 carrier-borne planes;

(b) 5,000 ground troops;

(c) From 19 to 25 vessels consisting of 1 aircraft carrier; 3 to 4 cruisers; 1 to 2 submarines; 6 to 8 destroyers; and 8 to 10 transports.

(3) Other groups.—(a) Landings in China.—Practically all Japanese landings in China were made with a force of two divisions (40,000 men or less). Equipment taken ashore included 3-ton tanks, 105-mm. field howitzers, and 75-mm. field guns. The Yuhung River landings by the Nakamura Detachment in 1939 which led to the capture of Nanning, China, involved only about 3,500 troops.¹ The force consisted of the following units:

(b) Naval landing parties.—These are trained to perform missions similar to the United States Marines. They engage in combat in cooperation with army units or act independently, and they are also used frequently to garrison enemy territory taken over by the navy.

Usually a naval landing party is an improvised battalion which consists of 2,000 officers and enlisted men organized in 4 companies. Three of the companies have 6 rifle platoons and 1 machine-gun platoon in each, whereas the fourth company has 3 rifle platoons, 1 machine-gun platoon, and an artillery unit of 4 guns. Additionally, a party sometimes has tanks and armored cars attached when serving in a garrison capacity.

Naval landing parties are trained and equipped to undertake any type of land operation within the scope of their numerical strength. All naval personnel are trained concurrently in both land and naval warfare. The training begins when the individual enters the service and continues ashore and afloat, as opportunity offers. The individual's progress in both phases of combat is noted on his service record by his superiors, together with any special qualifications he may possess. The landing parties are selected from those having the best records. The navy, therefore, possesses at all times a large number of personnel qualified for landing and land operations.

b. Ship Loads

The allowance for transport by water is about 4 to 5 tons per man. Normally two or three transports carry two-thirds of the troops, and the remaining smaller vessels carry the supplies and the remainder of the troops.

3. LANDING OPERATIONS

a. Preparations

(1) Preliminary.—For a number of years Japanese officers and secret agents, disguised in many cases as fishermen, gathered pertinent military information in the areas which the Japanese attacked. The army even had meteorological experts assigned throughout the islands of the southwest Pacific and in Malaya, Burma, China, Thailand, and Indo-China until as late as September 1941. Many of these men, including professors in the science of meteorology, were employed as laborers on rubber plantations and in rice fields and tin mines. They made particular studies on the beginning and the ending of the monsoon.² Their findings were based on rainfall, atmospheric pressure, temperature, and sun-spot observations. The army claims that the studies enable it to forecast when the monsoon will begin, how long it will last, and whether it will be normal, wet, or dry.

The timing and routing of Japanese military thrusts in recent months indicate careful study and full consideration of weather factors. The staff of each field army includes commissioned meteorologists and enlisted assistants.

In all their recent landing operations the Japanese have made air reconnaissance weeks ahead of the landings. Besides aircraft, secret agents and submarines have aided in making early reconnaissances. In each instance to date, the Japanese have selected landing sites within 400 miles of at least one Japanese air base.

(2) Final.—Submarines usually make additional reconnaissance ahead of the task forces. Long-range planes—which may be flying boats—follow up with more reconnaissances and also light daylight attacks. Type 96 heavy bombers, usually unescorted by fighters, then make light attacks to damage runways, destroy airdrome installations, get data on the opposition and secure weather information.

However, if the first group of reconnaissance planes detects concentrations of defending aircraft on airdromes in the vicinity of the objective, a surprise raid in force is made to destroy the planes on the ground. Planes used in the raid include high-level-type bombers, dive bombers, and fighters. The dive bombers and fighters concentrate on planes dispersed within revetments near the field, since the revetments lend a considerable measure of protection from high-level bombers unless direct hits are scored. The Japanese keep a close watch for replacements on the airdromes and maintain sustained attacks until defending planes have been destroyed or forced to leave.³

A final heavy bombing attack is made before darkness on the night the landings are attempted. Usually 50 to 150 aircraft make the attack to destroy communications, coast defense batteries, and antiaircraft installations. The air attack sometimes is assisted by warships which shell the defense areas from positions offshore. The ships can achieve howitzer fire by high elevation of guns and use of a reduced charge.

The approaching convoy is protected doubly on the day before landings are attempted. Direct air reconnaissance is given from all bases and carriers within range, and harassing attacks are made on opposition air bases from which attacks could be made on the convoy. If a suitable anchorage is available, troop ships, landing-boat carriers, and supply vessels stop for the night preceding the landing attack. If no anchorage is available, the vessels arrive off the designated landing place between midnight and dawn.

The Japanese do not consider rough weather or unfavorable beaches as obstacles; in fact, such conditions sometimes are chosen deliberately and considerable loss of life by drowning is accepted in order to achieve surprise. The time for the landing operations usually is 2 or 3 hours before high tide, on moonless nights if possible. This rule is broken only for strategical or navigational reasons.

If feasible, a few landing craft with engineers try to gain the shore secretly, before operations begin, to set up small lights—not visible from inshore—to guide the landing craft. In some instances, Fifth Columnists install the lights for the engineers. As a rule, at least part of the landing boats reach the beach before daylight. From 5 to 16 miles of shoreline are utilized for the landings.

b. The Landing Battle

Warships—which include cruisers and destroyers and sometimes aircraft carriers—form a protective screen around the troop transports during landing operations. Their guns are set to fire either at opposing aircraft or onshore batteries. Meanwhile transports carrying the advance assault troops go as near the shore as feasible before the troops disembark in small motor-propelled landing boats.⁴

A heavy machine gun and a light machine gun⁵ are set up near the bow of each boat for the landing attack, and each man, not otherwise engaged, has a rifle or a light automatic weapon to fire. Patrol boats armed with pompoms and machine guns give close support to the landings. Air support is available if needed. If used, it is under radio control of the landing units. The bulk of the air task force is held in reserve to counterattack opposition bases within effective range.

When very near the shore the Japanese, all equipped with life jackets, plunge into the water regardless of its depth, since the waves will carry them to the shallow water. If at all possible, the Japanese try to land with the initial force some light artillery, usually mountain-type (75's), and light tanks. Transports with the main body of troops remain some distance from the shore until the beach has been secured. Then the remainder of the troops are disembarked. The landings are directed either against fixed objectives or into localities which will permit flanking movements. Earliest landing parties use radio to direct air support.

c. Action after Landing

Once having established a beachhead, the Japanese push inland rapidly, carrying out thorough air and ground reconnaissance ahead of their advance units. Automobiles, bicycles, gasoline, and other supplies are confiscated quickly, and small groups, making the fullest possible use of darkness, penetrate the lines of the opposition to harass defended positions from the rear, cut communications, and attempt to force withdrawals.

If unopposed at the beaches, the Japanese hold to the roads, as a rule, until making contact with the opposition. They also use rivers and creeks to penetrate inland by boat and to turn flanks. They have special craft for such operations, including pontons propelled by outboard motors and boats driven by airplane-type motors with propellers rigged above the surface of the water. Smoke screens are used freely to facilitate inland movements. To avoid being fired on by their own planes, Japanese patrols and smaller units out in front are required to identify themselves during daylight with Rising Sun flags displayed toward the sky.

Meanwhile, immediately upon landing, parachute troops or special units of ground forces try to seize airdromes from which fighter planes may operate (protection of ground troops the first day usually is provided by seaplanes or carrier-based aircraft). Fighter squadrons are formed quickly, and from one or more seized airdromes, or from carriers, type 0 navy fighters come to the support of troops as quickly as possible.

Native labor is put to work repairing and resurfacing airdromes and extending them for use by heavy bombers within 2 to 7 days. Within 14 days, prefabricated shelters are put up, interceptor units are installed, and an aircraft warning service is spread over a 60- to 100-mile area. There also is evidence of searchlight installations being correlated with effective sound detectors. Supplies are accumulated and at intermediate points service and maintenance units for aircraft are set up—all within a period of 2 to 3 weeks.

The Japanese are great believers in thorough reconnaissance—a fact definitely established by translation of the captured orders dealing with the landing operations which led to the capture of Nanning. They seek information about the opposition by use of air reconnaissance and scouts; by questioning prisoners (especially high-ranking officers); by scrutinizing local newspapers, annuals, and other literature in occupied towns, and captured documents; and by careful estimation. The information obtained is sent immediately, by radio if practicable, to unit headquarters.