i june 1945 UNCLASSIFIED
JAPANESE ANTITANK WARFARE
"KNOW YOUR ENEMY!"
Classification to o: r
& £ 4K&ER' M*., S vV
C in CPac - C inCPOA BULLETIN 144-45
i IMS UNCLASSIFIED 4 m Po (U-i at- d~ 137% FOREWORD
Information contained in this pamphlet, which supersedes CINCPAC-CINCPOA BULLETIN 160-44, has been compiled from various sources and includes pertinent data on Japanese antitank tactics and weapons used against Allied armored forces.
Corrections ami additions will be made from time to time and recipients are invited to forward additional data to the Joint Intelligence Center* Pacific Ocean Areas.
Additional copies of the pamphlet are available on request.
'•V.
JICPOA L" 50603*# THRU 39 JAPANESE ANTITANK TACTICS
The evolution of Japanese antitank warfare from the start of the Pacific war, indicates a steadily increased emphasis on antitank defenses, organization, tactics and equipment.
Initially, Japanese antitank tactics were based on experience gained in skir mishes against Russian tanks. Training documents captured during the early part of the Pacific War were based on the Japs1 knowledge of Russian light tanks and tank tactics. Subsequently, the Japanese developed antitank warfare from small, meagerly equipped, independent assault teams and antitank gun units, to well equipped, highly specialized, coordinated units.
On Tarawa, 37 mm antitank guns were emplaced on beaches where they could be fired along tank approaches. Although the enemy was trained in laying hasty and deliberate minefields, only scattered mines were encountered offshore. A few in effective field expedients were found inland.
Antitank obstacles and antitank ditches, on the other hand, usually have been well-constructed and integrated with such personnel obstacles as trip wires. Ex perience has shown that the Japanese always will make the most of local materials in constructing obstacles.
Explosives prepared in the field have been unique and in some cases impracti cal, but steady improvements and variations have appeared.
Probably the most recent departure from normal antitank defense was employed by the Japanese on Iwo Jima. The enemy effectively used his light and medium tanks, the latter mounting 47 mm or 57 mm guns, as stationary dug-in fire points. His tanks were well concealed in emplacements covering our tank approaches, with only the tank turrets exposed.
Special Assault Teams
Close-in antitank teaaa were first organized to supplement inferior and inade quate antitank weapons. These groups have grown from two-, three-, and four-man teams, into sections of six to nine men equipped to deliver a comparatively heavy attack.
Raiding groups, developed earlier in the war, still follow fundamental Japa nese AT doctrines. Groups of three or more men are organized to slip through front
PAGE I lines, hunt out tank parks and destroy vehicles. The raiders, who also strive to destroy artillery positions, command posts, supply dumps and airplanes, are equipped with grenades, small mines, incendiaries and satchel charges. .Raiding units may be included in each infantry platoon, or organized from engineer units. The raiders attempt to maintain the element of surprise by attacking at night without support from small arms fire.
Still another mission of the raiding teams is to assault tanks which are de ployed or engaged in actual combat. These attacks are supported by small arms fire from accompanying infantry for the dual purpose of pinning down our tank supporting infantry and forcing the tanks to "button up".
If the situation permits, the raiders attempt to knock out our command tanks before attacking others. This is particularly true when maneuver is difficult and subordinate tanks are dependent on the leaders.
Each member of the raiding teams has a specific responsibility during an attack. One man places a demolition charge under the tank tread and another tosses a itolotov Cocktail, attempting to force the occupants of the tank to abandon it. If the crew continues to offer resistance, the raiders are trained to board the tank and force the ports with grenades and small aras fire.
Interrogation of two prisoners on Okinawa revealed that on 1 May, the 32nd Army ordered the 23rd and 26th Shipping Engineers and the 24th Division to send 15 men from each of their companies to Shuri. These men were ordered to construct a perim eter of camouflaged foxholes (spider traps) on all possible tank approaches in the area. From these foxholes raiding attacks were to be made on our approaching tanks. The raiders were to attack from underneath the tanks as they crossed over the fox holes, or from the rear after they had passed, using sticky grenades and improvised mines.
Priority list of vulnerable tank parts, which raiders attempt to hit, appears to be:
(1) Treads. (2) Rear of the tank, including air vents. (3) Front of tank, especially observation ports. (4) The turret, particularly where it joins main body. (5) Tank weapons.
In making attacks, the raiding units are cognizant of the importance of select ing terrain where the speed of tanks is limited. Steep inclines, fords, and ob stacles are used as points from which assaults are launched. The raiders&rive to catch Allied tanks which have been damaged and cannot maintain speed, or those which have reduced speed in order to fire.
The recently employed "raiding sections" have been divided into three teams: (1) Neutralizing team, (2) Track-attacking team, and (3) Demolition team.
The first attack is by the neutralizing team which is responsible for opening opportunities for the other teams to execute close assaults. The neutralizing team
PAGE 2 ^ PLANS FOR TANK ATTACKING TEAMS
MATERIAL FOR ATOICKING TANKS ARTIFICIAL OBSTACLES
TO ECHELONED TRENCH EMBANKMENT MOAT LAN D LAND RENDER TAN KS TANKS TO NEUTRALIZE TO DESTROY DEPTH MIN ES MINES TOP IN BASE IMMO OF BILE WIDTH DEPTH CLINE HEIGHT WIDTH WIDTH WATER 4 3kg 2 or Conical more Hand thrown smoke candle; 5kg Hemispherical Mine; M-L Hand Yard Conical hand thrown mine Light armor - 2kg Conica]I 6,6" 2/1 8«2" 231 29'6" 6!6n HEAVY Thrown stick Type 99 Magnetic mine* hand thrown mine and 5kg Mines Mines Improvised mine.
2 Type Yard 1 Conical hand thrown M-4 , n 93 stick SAME mine or 3kg Improvised 13 fl" 6 6" 3/1 6»5 19•?« 24f U x MEDIUM Mines Mine mine.
Main parts 1kg Conical M-3 SAME SAME SAME hand thrown mine; Others 13 fln 6,611 3/1 6f5,f 19 *7" 241 A 1 3kg Improvised mines.
Type 1kg Conical hand thrown BIT-2 mine; Light parts 1kg 13 tin 6*6" f 16•5" x MEDIUM 93 SAME SAME 3/1 . 6 5" I9.7H K Mine Improvised mine; Type 99 Magnetic mines.
Smoke against turret tra M2-A3 Type 99 Magnetic mine or , LIGHT SAME SAME versing mechanism; Hand 9,8M 41 3/1 4f 13*1" 16*5" 3 11» grenades against guns. 1kg. Improvised mine.
2 Conical hand thrown Yard Hand thrown smoke candle; mines or Type 99 Mag M-3 SAME stick Conical hand thrown mine netic mines. Lighter 9I8" 41. 3/1 6f6" 16*5" 16»5W 3,11« LIGHT Mine and Type 99 Magnetic mine parts 2 - 1kg Improvised mines•
Smoke against turret tra F Kl-Al SAME SAME versing mechanism; Hand Type 99 Magnetic mine or 9 8». 4* 3/1 4* 13'1" 16*5" 3 r H" LIGHT grenades against guns. 1kg Improvised mine. uses smoke to blind the tank occupants. This action is followed by hand-thrown mines and grenades to eliminate the crew. Against flame-throwing tanks, the team employs smoke grenades shot from a launcher placed out of range of the tank guns.
The track-attacking team then moves in on the crippled tank and destroys its tracks with yardstick and tape-me&sure mines attached to poles. In most cases the team concentrates on one track. Final destruction is left to the demolition team, which attacks the armored parts of the tank and destroys the crew.
Japs are given special individual training in tank raiding tactics and are quick to take advantage of our tanks which have outdistanced supporting infantry. They all are imbued with the spirit of becoming "human bombs" if they are called upon for any such mission. Though they are resolved to "die for the Emperor", re cent training doctrines have stressed the importance of making death as costly as possible to their enemy.
Each member is expected to account for at least one U. S. tank. Itany of the attacks will seem foolhardy to us, but the Japanese are determined to make us pay a heavy price in men and armor.
Our best defenses against Japanese close assaults on tanks are: Close support by infantry; mutual support by tanks; fast movement of the tanks; tank accessories designed to prevent boarding and attachment of demolition charges.
Tactical Employment of Antitank Guns
Most Japanese infantry battalions have at least two antitank guns, organized as a platoon in the battalion gun compar^y. Depending on organizational differences, this platoon may have three, or even four guns, although two guns seem to be stan dard. Previously, four and sometimes six AT guns were included in a regimental AT company. These weapons have been placed in battalions during recent Central Pacific operations. It is entirely possible that the regimental AT company again will be encountered, or that combination regimental and battalion AT units will be met.
In recent campaigns, AT battalions with a normal armament of 12 47 nam AT guns have been attached to defending infantry forces to supplement antitank and antiboat capabilities. Five such units were included in the Iwo Jima garrison and several have been encountered on Okinawa.
In addition, two automatic guns for close-in AT support (usually Type 97 20 mm) may be included in the machine gun company or in the machine gun platoons if the latter are organic within the infantry company. Although basically AA weapons, Type 96 20 mm and Type 96 25 mm may be used for AT purposes.
The use of Type 90 75 mm field guns in AT roles was first encountered on Luzon, and more recently on Iwo. On Luzon, many of these pieces were placed along roads. They permitted our tanks to pass and then fired on them from the rear. This muzzle-
PAGE 4 braked gun, capable of knocking out medium tanks, was not used at ranges exceeding 500 yard8. The 37 and 47 mm guns, operating in conjunction with larger weapons and machine guns, were relegated to supporting AT roles. They were charged with harass ing and damaging our tanks and reducing their speed, or forcing them into fire traps where the Model 90 75 mm field gun could fire on them with maximum efficiency.
Additional antitank support frequently comes from independent AT units of either battalion or company strength. These units are attached for direct support. The battalion consists of three companies with four 47 mm guns each, as shown in Chart 1-A. Chart 1-B illustrates the independent company with its eight guns, and Chart 1—C shows an older battalion organization with two six-gun companies.
Tables of organization for tank destroyer units (Charts 1, J, and K) give an excellent idea of the extent of diversification the Japanese hope to develop in AT warfare. Thus far these units have appeared only on paper and have not been en countered in actual operations.
Antitank defense on Iwo Jima received special emphasis on pre-invasion prepara tion and actual engagement of U. S. forces. The importance attached to this defense is shown in a plan of battle which was drawn up for the defense of the island. The main essentials for antitank warfare were set forth as follows:
"Tanks in the vicinity of the sandy beaches, where maneuver is difficult, will be destroyed by land mines, shelling, and close quarter attacks. After beachheads are established, close quarter attack forces will exploit confusion caused by shell ing and carry out raids upon tank groups at night. Near the main positions, tank movements will be restricted by terrain, obstacles, and antitank ditches to such an extent that antitank guns (Japanese), tanks, and close-assault teams can be coor dinated and employed with maximum efficiency. All forces will make preparation for close quarter attacks."
Chart 1
UNIT STRENGTH ORGANIZATION WEAPONS
Ind AT Bn 491 12 37am or U7wm AT Guns 53 BH HQ 110-126 ea. 3 Coa 4 37*a or 47®m AT Guns ea. "A" 15 ea. Comd Sect 41 ea* 2 Platoons 2 37mm or U7vn AT Guns ea. 13 ea. 2 Gun Sects 1 37nm or 47nm AT | Guns ea• 14 Ammo Sect 27 Anno Platoon 60 Bn Ammo Train
Ind AT Gun 143? 8 47mm AT Guns Co 13? Comd Sect 42? ea. 2 Platoons 4 47mm AT Guns ea. "B" 10-11? ea. 4 Sqds 1 47mm AT Gun ea. 1 42? Ammo Platoon
j (Old) Ind AT 350 12 37mm AT Guns j Gun Bn 48 Bn HQ 150 ea. 2 Cos 6 37mm AT Guns ea. IV 1 Comd Sect j HQM 30 ea. 3 Platoons j 2 37mm AT Guns ea. 18 Ammo Sect 1 52 j Ammo Train ; i - 1 CHART I Unit Strength Organization Weapons Tank des 790 12 37 mm AT guns troyer unit 3 37 ma AT guns mounted on (Fteinf Ind three tanks AT Gun Bn) 4 Type 38 Fid guns 2 Flame throwers 86 Hq 65 Liaison Sect 5-33 ea 4 Radio Sqds 7 ea 2 Wire Sqds 20 Comd Sect
206 1st Co 26 Comd Sect 47 ea 3 Platoons 11 ea 3 Sqds 11 Gren die sqd 39 MG Plat 9 ea 4 Sqds
135 ea 2d & 3d Cos 6 37 mm AT guns ea 23 Comd Sect 35 ea 2 Batteries 3 37 mm AT guns ea 11 ea 2 Sqd8 11 Gren dis sqd 35 Inf Platoon 11 ea 2 Sqds 11 Gren dis sqd 7 Ammo Platoon
112 4th Co 4 Type 38 Fid guns 22 Comd Sect 24 ea 2 Batteries 2 Type 38 Fid guns ea 11 ea 2 Sqds 1 Type 38 Fid gun ea 35 Inf Platoon 11 ea 2 Sqds 11 Gren dis sqd 7 Ammo Train 12 Recce Platoon 3 37 mm AT guns mounted on three tanks 63 Engr Platoon 2 Flame throwers 13 ea 4 Sqd8 6 Tool & Material Sqd 41 Supply Sect
PAGE 6 CHART J Unit Strength Organization Weapons Tank Des 698 6 37 mm AT guns troyer Unit 4 Type 38 Fid guns (Inf Bn as the basis) 86 Hq 20 Comd Sect 65 Liaison Sect
206 ea 1st & 2d Cos 26 Comd Sect 47 ea 3 Batteries 11 ea 3 Sqds 11 Gren dis sqd 39 MG Platoon 9 4 sqds
137 3d Co 6 37 mm AT guns 23 Comd Sect 24 ea 3 Batteries 2 37 am AT guns ea 11 ea 2 Sqds 1 37 mm AT gun ea 35 Inf Platoon 11 ea 2 Sqds 11 Gren dis sqd 7 Ammo Platoon
112 Alternate 3d Co 4 Type 38 Fid guns 22 Comd Sect 24 ea 2 Batteries 2 Type 38 Fid guns ea 11 ea 2 Sqds 1 Type 38 Fid gun ea 35 Inf Platoon 11 ea 2 Sqds 11 Gren dis sqd 7 Ammo Platoon 63 Engr Platoon 13 ea 4 Sqds 6 Tool & Material Sqd
PAGE 7 CHART K Unit Strength Organization Weapons Tank Des 780 8 Type 38 Fid Guns troyer Uait 6 37 mm AT guns (Reinf Ind 3 37 mm AT guns mounted AT FA Bn) on three tanks 2 Flame throwers 92 HQ 5-33 eal 4 Radio Sqds 7 ea 2 Wire Sqds 206 1st Co 26 Cosad Sect 47 ea 3 Platoons 11 ea 3 Sqds 11 Gren Dis Sqd 39 KG Platoon 9 ea 4 Sqds 112 ea 2nd & 3rd Cos 4 Type 38 Fid guns ea 22 Comd Sect 24 ea 2 Batteries 2 Type 38 Fid guns ea 11 ea 2 Sqds 1 Type 38 Fid gun ea 35 Inf Platoon 11 ea 2 Sqds 11 Gren Dis Sqd 7 Ammo Platoon 142 4th Co 6 37 mm AT guns 23 Comd Sect 24 ea 3 Batteries 2 37 mm AT guns ea 11 ea 2 Sqds 1 37 mm AT gun ea 35 Inf Platoon 11 ea 2 Sqds 11 Gren Dis Sqd 7 Ammo Platoon 12 Recce Platoon 3 37 mm AT guns mounted on three tanks 63 Engr Platoon 2 Flame throwers 13 ea 4 Sqds 6 Tool & Material Sqd 41 Supply Sect
PAGE 8 In addition to these plans and preparations, the Japs on I*o demonstrated co ordination of artillery and mortar fire to a greater degree than had been experi enced previously by our troops. Mortar and time fire were used against infantry working with our tanks.
In beach defense* AT guns, supplemented by field, coast defense and AA guns, were emplaced at the beach line to serve anti-boat missions. Direct fire was em ployed with each weapon assigned primary firing lines, thus producing interlocking bands of fire in front of beach barricades and obstacles. On Tarawa, boat barri cades were tactically situated so that they led approaching craft into fire traps. On Saipan, one field gun held a pass and denied entrance to tanks most effectively until it was knocked out.
Uuch of the terrain on Okinawa was favorable for antitank defense, and the Japs took advantage of it in several localities. In addition to the open or built- up covered 47 mm AT gun positions found on Iwo, many tunnels which provided ade quate protection from light artillery were dug into Okinawa hills as antitank gun emplacements. These tunnels were so placed as to cover likely tank approaches and enabled the gun crew to deliver fire on the rear and flanks of our tanks. They were dug straight back into the hills for about 20 feet and then to one side at an angle of about 45 degrees. Some had two or three firing points leading out from the tunnel, which gave the gun a much larger field of fire. The small firing ap ertures were skilfully hidden with camouflage flaps. Although this weapon has an appreciable muzzle flash, several crew members whose tanks had been hit stated that they had seen neither the flame in nor smoke of the Jap guns. In one instance two guns, emplaced in defilade covering an approach through a defile allowed a platoon of our tanks to pass. Then they opened a rapid rate of fire on the tanks* rear from close range.
In normal land operations, the Japanese place their guns as far forward as possible, but leave a number of weapons in a rear position to act as reserve guns and to give defense in depth as much as terrain andthe situation permits. Conceal ment and camouflage are stressed*
Positions will be selected for best coverage of avenues of approach, and an infantry unit may be attached for local protection. Positions will take advan tage of natural terrain obstacles, and artificial obstacles will be employed where possible.
Tanks which approach a position and halt to deliver a bombardment to neutra lize Japanese positions are most vulnerable to the fire of well-concealed AT guns.
Until the Iwo operation, the tactical situation in the Pacific had permitted tanks to be used effectively for such a bombardment. However, only complete recon naissance which guarantees that no AT guns are in position can assure safety to tanks so used. Many times AT gun emplacements on Iwo were not discovered until after they had knocked out one of our tanks. Actually, tanks used for such close support of infantry become self-propelled guns rather than a mobile striking force.
PAGE 9 Each enemy gun normally will have 60 to 100 rounds of HE and AP ammunition. Replenishment is by the ammunition platoon which delivers to each gun squad from the company dump* The company dump draws from the battalion. Supply, generally follows a route from larger to smaller unit, the former furnishing both manpower and transportation. Almost every gun emplacement on Iwo was supplied with ammunition from its own dump thus doing away with any supply problem as long as the original position was still tenable.
In the Central Pacific when they lacked sufficient men and weapons, the Japa nese often did not cover obstacles by fire, but depended on obstacles and infantry to 8top tank assault* However, this tendency is more of an e>pedient forced by local shortages.
Antitank Obstacles
Tank Ditches and Barriers
The Japanese have made extensive use of natural obstacles and terrain features as a basis for siting tank ditches and barriers, utilizing these natural hazards to cover breaks in the barriers or ditches.
Areas between tank obstacles are generally cleared, with single and double- apron barbed-wire fences and trip-wires located on each side of the clearing and running parallel to the obstacles. Further protection is afforded these tank traps by siting heavy machine guns and/or antitank guns to cover the approaches.
Most tank ditches encountered in the Central Pacific have been of shallow de sign because of the high water table on most of the islands. They measured 5 to 7 feet deep and 12 to 16 feet across. A few ditches have been found with concrete sides or logs placed vertically in the bottom as an added impediment.
Antitank ditches were prepared throughout the level portion of an island and at the landward edge of the beach to deny avenues of probable tank approaches to the more vital installations further inland. "V" Type antitank ditches were pre pared throughout those areas where tanks would be most likely to travel. These ob stacles were often in the form of short, unconnected trenches and were prepared in a broken line of segments 20 to 30 feet in length with a 20-foot interval between trenches. Usually the ditches are supported by antitank barriers constructed of coconut logs braced with diagonal logs or attached to trees with rope or wire. These barriers vary in height from four to eight feet and are generally placed in straight line segments, as are the ditches. Although it is the general practice to erect log barriers inland or along the beaches, they have also been encountered on the reefs. At Tarawa, this type of obstacle consisted of two rows of coconut logs horizontally placed and braced with other logs at three-foot intervals. It measured six to ten feet in height, with the braces extending two or more feet above the top of the ob stacle. All joints were wired or held together by large steel staples. Virtually the entire obstacle was interlaced with barbed-wire, complicating the task of de molition parties. PAGE 10 Characteristics of terrain on Iwo precluded the use of barricades. The coarse volcanic sand not only made tank movement sluggish, but made easier the digging of tank ditches. Conversely, barricade erecting would have complicated any obstacle dependent upon the soil for anchorage. Farther from shore, the terrain generally was so rough that tank maneuver was restricted to narrow approaches, which were more suitable to mining. Almost all the perimeter on some of the Pacific Islands has been protected by a tank barricade, composed of two courses of 30-pound rails lashed to coconut logs set vertically in the sand or coral. It is believed, how ever, that this barricade would not prove an obstacle to anything except light tanks. It has been destroyed quite easily by shellfire.
Other antitank barriers, in the form of concrete protective walls with anti tank or machine gun positions emplaced within them, sometimes are placed along the beaches and in front of strong points. Uany islands have seawalls of heights vary ing from four to twelve feet, with rocks or small logs emplaced in them, forming obstacles for personnel as well as tanks. Along the tops of these seawalls may be found log barricades, or single, double or triple-apron barbed-wire.
At Tarawa, the root-ends of large coconut logs were embedded in the sand or coral as an antitank obstacle. Only where the beaches were covered by effective bands of fire, as on Tarawa, would an obstacle of this type afford much protection.
A peculiar type of barrier was noted at Makin Island, where tank traps extended from the lagoon to the ocean shore. To prevent tanks from using the reef to cir cumvent the obstacle, two rows of coconut logs, extending two feet above the ground, were placed 165 feet out onto the reef. The apace between the rows was five to seven feet wit£ the logs interlaced with barbed-wire.
Under-Water or Reef Obstacles
In support of the usual tank and boat barricades, four to six-foot piles of coral rock, measuring six to eighteen inches in diameter, and concrete tetrahedrons have been placed on the reefs to canalize tanks or landing craft into areas covered by fire from well-emplaced weapons. These are placed in a series of straight-line segments with mines laid at intervals between the obstacles.
The mines are, for the most part, ten to fifteen feet apart and placed between two tetrahedrons or rock piles with wire connecting the detonator to the angle-iron corners of the obstacles. Experience indicates that sympathetic detonation does not result if one mine is set off. Both tetrahedrons and the rock piles are placed on the reef so the tops just clear the water at high tide and are so close together that tanks or landing craft will not pass between them. While most of the offshore tank or boat obstacles at Guam were haphazard, they are worthy of note. They were of two types, the first consisted of simple square log cribs approximately three feet square, filled with coral rock. The other con sisted of several segments of logs placed together horizontally and tied at the joints with heavy net-type wire. In same instances the wire rolls were further an chored by partly filling them with coral rock.
PAGE II Minefields
With sufficient time to plan and install minefields, an effective defense against tanks may be accomplished. Prior to the fighting on Iwo, however, the enemy had not made the most of his capabilities in this respect. For a minefield to be most effective, it must be placed in tactically correct terrain and covered by small-arms fire. Our troops have encountered several hastily-planted minefields in the Pacific, some fairly well planned and following a definite pattern, but, un til I*©, none could really be classified as deliberate.
Japanese documents captured early in the war indicated that the Japs were cog nizant of the tactical employment of minefields. However, prior to the Iwo cam paign, either because of a shortage of land mines or inability to use them effi ciently, no effective minefield had been encountered once we reached shore. On Tarawa, extensive use of mines was made on the beaches and offshore, but these were employed primarily as antiboat mines. Within the perimeter of defense, mines were noticeably absent. In the Marshalls, no adequate minefields were encountered. Those found on Saipan were extensive but haphazard. Hastily-improvised bombs, shells, and torpedoes had been rigged as mines.
Recognizing well in advance the necessity of holding Iwo, the Japanese for the first time in their Pacific defenses resorted to deliberate minefields. Despite limited utilization of mines according to our standards, minefields were more stra tegically located than ever before and in all cases were covered by fire. However, they usually lacked sufficient depth. The two most heavily mined areas were the East and V»est Beach zones. A strip of the East Beach along the shore line was mined with a series of short individual fields. These fields were supported in depth by additional hasty installations laid across roads and other routes of advance. One extensive field ran from airfield No. 1 to the shoreline where penetration would endanger the upper half of the island.
Standard pattern of O O O O O O O O O O O 1 minefields was employed 7-15 PACES on Iwo Jima. The mines, o o o o o o O O O o O 1 — spaced 7 to 25 paces, were placed in rows app O O O O O O O O O O O roximately an equal dis tance apart. The mines in one row were stagger ed between mines of ad 7 -25^ PKIS jacent rows. Figure 1 - Typical pettern of minefields The increasing use encountered. of mines, the develop ment of new mines, and the trend toward greater mine defenses, indicate that the enemy will employ them even more adequately in the future as an antitank measure.
PAGE 12 ANTITANK WEAPONS
Against our annored forces the Japanese have used antitank guns, grenades, and antitank mines, but continually they have demonstrated marked ability to improvise counter-measures from available materials. Aerial bombs, blocks of explosives and other materials have been so used.
Older mines such as the Type 93 and the Yardstick have been adapted for use as one-man,close-in attack weapons. New mines to be placed on a tank or thrown from a short distance still are being devised.
Non-metallic mines like the Type 3 terra-cotta and wooden mines which cannot easily be detected by ordinary mine detectors are being used in increasing numbers. This possibly is due to a shortage of metal.
Qnphasis is being placed on the use of the Type 1 47 mm and the Type 90 75 mm guns with the Type 94 37 mm gun still being used as probably "substitute standard".
Descriptions and capabilities of various antitank mines and weapons are con tained in the following paragraphs.
Considerable emphasis has been placed on the effect of Jap mines and weapons against our light and medium tanks. It should be borne in mind, however, that these weapons are even a greater threat to our half-tracks and the lighter armored vehicles that supply and maintain heavier armored equipment.
Mines
The Type 99 Magnetic Antitank mine has been encountered in almost every campaign against the Japs. It is used primarily by neutralizing teams as a weapon of the indi vidual soldier. The four magnets about its perimeter and the 10-second delay fuze set it apart from other antitank mines thus far en countered. The mine, if used alone, will penetrate 3/4 inches of armor plate and, if used in pairs, will go through l£ inches. Re sults of tests on medium-grade steel plate re veal a penetration of l£ inches and l| inches for single and double mines, respectively.
The mine weighs 2 5/8 pounds and contains lj pounds of explosive variously described as picric acid, TNT, and cyclonite and combina tions of these. The canvas bag which encases II Type 99 Magnetic Mine PAGE 13 the explosive is 4 3/4 inches in diameter and l| inches thick. A carrying bag which can be attached to the soldier's belt is provided. The fuze is packed sep arately in a cylindrical metal container in the top.
A larger model weighing five to six pounds, similar to the smaller one descri bed above, has been encountered and improvised mines have appeared, consisting of a length of fuze cord and friction igniter attached to blocks of e:q?losive to which magnets were added.
i •; ' id. ii * 6 m i
m
Type 93 Mine attached to pole Type 93 "Tape-Measure" Mine
TAPE MEASURE MINE
60ARD
Type 93 Tape-Measure Mines rigged with boards.
The Type 93 "Tape-Measure" Mine also has been found in most operations, but re cently it has been relegated to a secondary role.
By using different shear wires in its fuze, it has been employed as an anti personnel or antitank mine. Members of tank-neutralizing teams have attached a Type 93 mine to a bamboo pole arcl struck them against passing tanks or placed them under tracks. A rope may be attached by which the mine is moved across the ground in the
PAGE 14 tank's path. Recently mines have been found in pairs, back to back, with or without hard grenade or other explosives attached. In a field of 100 of these mines in Burma, 20 were equipped with anti-lifting devices consisting of small cloth bags filled with picric acid and equipped with a pull-igniter which was attached by a short cord to the rings on the sides.of the mines.
The Type 93 mine weighs three pounds and contains tvo pounds of picric acid or a mixture, half TNT and half cyclonite. The tin case is olive drab in color, approximately 6 3/4 inches in diameter and 3/4 inches thick. The fuze is covered by a light metal cap and is detonated by a pressure of 30 to 70 pounds if the anti personnel shear wire is employed. A pressure of about 250 pounds is required if the heavier antitank shear wire is used. The Japs have claimed one of these mines will break the track of a light tank. They prescribe two for stopping a medium tank.
The Japanese have not used the Dutch "Mushroom Top" land mine in this theater. It is possible they have ex hausted their supply of these captured mines.
The "mushroom" type cover is held in place on a helical spring. With a light wire in its fUze as a shear wire, a pressure of only 50 pounds on any part of its large surface will cause detona tion, making it an effective anti-per sonnel mine. When used as an antitank mine, a shear wire withstanding a pres sure of 180 to 240 pounds replaces the lighter shear wire. Dutch "Mushroom-Type" Mine The mine is olive drab in color and has a steel sheet case. It is eight inches in diameter and somewhat hemis- pherical in shape. Total weight is is, of which 5i pounds is cast TNT.
It will break the tracks of our medium tank and cause casualties to its per sonnel.
Yardstick
Mine
PAGE 15 YARDSTICK M»Nt
« OR 250 K&. BOMB NO. it \m
Yardstick mine employed to detonate aerial bomb.
Depth Charge with GRtNME DETONATOR improvised igniter WOOOEN PLUG employed as land mine. TIME FUSE.
WOODEN PLUG
NON - ELECTRIC CAP
// PISTOL
The Yardstick Mine is so-called because of its length: 36 inches. In a test, one of these mines broke the track and severely damaged the rear idler of a U. S. light tank, penetrated the bottom and threw shrapnel inside. There is no doubt that it will break the track of a medium tank.
The mine weighs 10 3/4 pounds and contains 6 pounds of picric acid. Four fuzes are spaced through the length of the mine, thus increasing the area over which it may be detonated. It is oval in cross-section, 3 l/3 by 1 4/5 inches, and olive drab in color.
With the copper shear wire in place, a pressure of 336 pounds is necessary to cause detonation of the fuze. Without the wire a pressure of only six pounds is needed. These raines have been tied across the horns of a JXIII hemispherical anti- boat mine, and also tied to a 63 kg bomb to increase the force of explosion.
PAGE 16 The capture of the Type 3 Terra- Cotta Land Mines marked a new phase in our observation of Japanese mine warfare. They were the first non-metallic mines recovered. The use of a bakelite fuze, with a minimum of metal, and its pot tery case, make this mine difficult to find with detectors. The unglazed case is earth-colcred and easily camouflaged.
Two sizes have been reported; one is 10| inches in diameter, 3s inches *,hick and contains 65 pounds of explo sive. The smaller is 8^ inches in dia meter and contains pounds of explo sive. The high explosive used has beea described as ammonium nitrate and TNT, or ammonium nitrate and ammonium per- <*,\ ; »• « > m *>v * J A I I SP ?•; ^| chlorate. Both mines are effective against the track of a medium tank.
Type 3 Terra-Cotta Land Mine As an anti-personnel mine, the larger model has a claimed effective radius of 33 feet and the smaller, 26 feet.
The fuze employed causes detonation by exertion of about 22 pounds pressure or a pull of about 5 pounds. The fuze is inter-changeable with the standard Type 88 or Type 100 artillery fuze, enabling the Japs to adapt their mortar or artillery shells as land mines.
Type 3 Model "A" Land Mine on right attached by trip wire Type 3 Model "B" (Wooden) to Type 3 Model "BM Land Mine Land Mine on left. PAGE 17 A manufactured wooden box mine referred to as the Type 3 Model "B" land mine was first found on Iwo Jima. It was equipped with the same combination pressure- pull fuze as used with the Type 3 (Terra-Cotta) Model "A" Mine.
This mine is 7 1/8 inches square, 4 7/8 inches deep and contains 4h pounds of Type 88 explosive (same amount as the small Type 3 Model "A"). The cover consists of half-inch boards nailed together with the top attached by six one-inch screws. The overall weight is 6 pounds; and its 4| pounds of explosive is encased in a rubber sack (Type 88 explosive is hydroscopic).
This mine, too, does not register with ordinary mine detectors. It may be assumed that it will destroy the track of a medium tank.
Hemispherical (J XIII) Anti-boat Mine on left. Conical (J XVI) Beach Mine on right.
Sea Mines
Conical beach mines (J XVI mines) have been employed both on beaches and inland as antitank mines. They are buried with only their leaden horns protruding above the ground. Some were found in groups of three with horns lashed to an 18 foot bar to increase the danger area. Weighing 70 pounds and containing 22 pounds of Type 98 explosive (60 percent TNT, 40 percent TNA), these mines undoubtedly would knock out a medium tank.
PAGE 18 The mine itself is shaped like a truncated cone, 12 inches high and 14 inches in diameter at its base. A single leaden horn is present, inside of which is a vial of acid. V.hen the horn is crushed, the vial is broken; acid runs down into a battery cup allowing electrical contact to be made by wires leading to a detonator. This in turn sets off the booster and main charge. The hemispherical anti-boat mines (J XIII) function in the same manner as the conical type. They weigh about 110 pounds and contain 46g pounds of the same type of explosive as is used with the conical beach mine. One of these mines will easily knock out any of our armor. The mine is hemispherical, 10 inches high and 20 inches in diameter at its base. Two leader horns protrude toward the top and there are two carrying handles. The mine is covered by a black steel case. Hand-Thrown Mines The Japs have developed several close-in antitank weapons. Mostly, they utilize the hollow-charge principle by which the force of the explosion is focused at one small point. Among these are the several modified conical, hollow- charge, antitank grenades.
The Type 3 Model "A" Conical Mine weighs 2 3/4 pounds, of which 1 7/8 pounds is Type 94 explosive (50 percent TOT and cyclonite). It is 6 3/4 inches long and 4 3/8 inches in diameter. At its top is a 14-inch tail of hemp added to help stabilize it in flight.- The cover is heavy leather. The fuze employed will function on a slight angle of impact. A small Type 3 Model "A" has been recovered.
The Type 3 Model »b" is the same as the Type 3 Model "A" Hollow Charge Model "A" except that it is slightly smaller (6 Conical Hand-thrown Line on inches long, weight 1 5/8 pounds), has a yellow right. Type 3 Model "B" on silk cover, a single-pronged safety pin in a left. modified fuze, and a tail of straw instead of hemp.
The Japs claim penetration of 2 3/4 inches of armor plate with the Model "A".
The Japs have developed 2 and 3 kg (4.4 and 6.6 pound) hollow-charge hand-thrown mines, according to documentary evidence. The 2 kg mines mentioned are equipped with the same delay fuzes as are used with the Type 99 magnetic antitank mines and are similar in shape to the Type 3 conical hand-thrown mines.
Based on the enemy's claim of a penetration of 2 3/4 inches of armor for the 1 kg mine, it is presumed that the 2 kg would penetrate 3 inches or more.
These mines were undoubtedly developed particularly for suicide squads. Four rings are provided near the base to which small ropes can be attached and the mine may be lobbed over or held against the side of a tank. Poles also have been tied to the mines for holding them against the side of the target.
PAGE 19 Three views of 2 kg Conical Hand-Thrown Mine
The 3 kg mine, according to the enemy sources, is shaped like other oonical hand-thrown mines and will penetrate more than 5 inches of armor.
Five kg (11 pounds) hemis pherical armor piercing mines are mentioned in Japanese docu ments but none has been en countered to date. These, too, are equipped with the same type delay fuze as is employed in the Type 99 magnetic mine, and are held against the side of the tank by a pole or ropes. The enemy claims this mine will penetrate almost 8 inches of armor plate. 5 kg Hemispherical AT Mine
A lunge mine which consists of a cone-shaped aluminum or steel body, 11^ inches long and 8 inches in diameter at its base, connected to a five-foot pole was encountered on Leyte. Three legs at the base help keep it in position against the tank. The shaped charge of crude INT weighs about seven pounds; the over all weight including handle, is 15 pounds.
Using the hollow-charge principle, this mine, according to the Japanese, can penetrate 6 inches of armor plate. The firing pin is at the lower end of a pole thrust into the mine. When the mine is picked up by the pole and crashed against the tank with a lunging motion of the soldier, the striker breaks a shear wire and sets off the detonator and main charge.
3-Kg LUNGE MINE
PAGE 20 Aerial Bombs
Beginning with the Saipan operation, 63 kg bombs have been extensively en countered as land mines. Recently they have been found buried horizontally with yardstick mines placed on top to detonate them. They have been buried nose up, some in definite patterns, with or without Navy A-3(a) fuzes.
The bombs are gray in color and weigh 132 pounds/ The 6lA, pounds of Type 9& explosive they contain will cause severe damage to any tank. Besides the 63 kg bombs, 30, 50, and 60 kg bombs have been employed as improvised land mines. In some cases they have been used as electrically-controlled mines and detonated from a dis tance behind cover.
Removal of 60 kg Bomb which had been laid as land mine.
Depth Charges
Depth charges were employed as land mines in the Philippines and on Iwo Jima. On Iwo, the Japanese Type 2 Modification 2 depth charge, weighing 352 pounds and containing about 220 pounds of Type 88 explosive, was used. The igniting device consisted of the striker and igniter of a Type 99(a) grenade placed in a wooden block attached to a length of time fuze (burning time, 45 seconds) which was fas tened to a non-electric blasting cap in a smaller piece of wood. The blasting cap housing fitted on top of a standard detonator into the well of a Type 2 Modifica tion 2 booster. This train filled the entire center cavity. When the grenade ig niter is struck, it starts the delay train which after burning its length set off the non-electric blasting cap, and in turn the detonator, booster and main charge.
Due to the long delay, this mine would not endanger the vehicle running over it but would severely damage following tanks or vehicles. The Japanese prescribe that this device be used as a"wheeled bomb" to ignite by hand and roll downhill in the face of a massed tank or infantry attack, but, to date, it has not been so used.
PAGE 21 •/-
// /
'J c
GUIOE FRAME PRESSURE PLATE PRESSURE PLATE ASSEMBLY
Grass 8 Earth
EZZZZZZZZ
DEPTH GUIDE FRAME CHARGE PRESSURE BLOCK STRIKER
DETONATER BOOSTER
At right, depth charge used as land mine—Ig niting device is shown in front.
Depth charge as Land mine as it appears from above.
JAP. HAW DEPTH CHARGE YPE 2,M0D.2
PAGE 2 2 On Luzon a simpler and much more effective device was employed to set off a similar depth charge. A pressure board held in place by a guide frame and attached to a wooden striker was installed. When pressure was applied to the 8 inch square pressure plate, the striker was driven against the detonator and an immediate ex plosion occurred. A crater 25 feet in diameter and 12 to 15 feet deep was formed by one of these charges. They will destroy any of our tanks.
Improvised close-in attack weapons encountered on Iwo Jima. Two Type 93 Tape-measure Mines tied together with Type 97 Hand Grenade on left. Single Type 93 Mine and grenade at right rear, and group of grenades in front.
Improvised Explosive Charges.
Many improvised mines have been encountered and described. Among the latter is a pole charge consisting of 32g pounds of demolition blocks attached to a pole and equipped with a Type 93 mine fuze.
Artillery shells with combination pressure-pull fuzes used in the Type 3 land mine have been encountered.
Various wooden boxes filled with explosive and fitted with fuze lighters or pressure devices have been recovered. Even sack charges of picric acid or some other explosive have been described. These probably are fitted with pull-igniters and are to be placed on vulnerable spots of tanks.
On Okinawa, Type 9^ "Stick" hand grenades were used as detonators in wooden boxes of picric acid to make improvised mines.
Prefabricated booby traps found on Iwo Jima. These are the suicidal, improvised mines which Tokyo instructed subordinate units to make and use against our tanks.
PAGE 23 Underside of top of prefabricated booby trap showing pull igniters attached to non-electric blasting cap and detona tor.
In July 1944, under imprint of Imperial General Headquarters and the War Min istry, instructions went to all troops to improvise mines to be used by suicide squads against tanks. They prescribe box mines made from 5 to 7 kg (12 to 15 pounds) of regular Type 97 picric acid blocks for attack against light and amphibious tanks, 7 to 10 kg (15 to 22 pounds) against medium and heavy tanks, and 10 kg or over against super-heavy tanks. One or two improvised firing devices consisting of a Type 1 pull-igniter, 1 cm (burning time, 1 second) of Type 1 Safety Fuze and Type 97 non-electric blasting cap were to be used. The prefabricated booby traps found on Iwo Jima and Okinawa fit this description and probably were intended for one-man attacks against tanks. These improvised mines will undoubtedly be met in large numbers in the future.
Grenades
Rifle grenades have not been omitted from the list of Japanese antitank weap ons. The Japs have devised 30 and 40 mm hollow-charge rifle grenades to be fired in the Type 2 grenade launcher. The launcher is a direct copy of the German cup- type and the grenades are similar to German models. The Japs have stated that this
ii# ii i i I 6
Type 2 rifle grenade launcher and 40 mm hollow-charge antitank rifle grenade. PAGE 24 Frangible grenade (Molotov Cocktail). Note fuze and fuze packing can at right.
aw o -4s. rifle grenade will penetrate from 1 to 2 inches of armor plate.
Tank hunting teams use a variety of auxiliary weapons. Smoke grenades fired from a Type 10 grenade discharger are used by tank-assaulting teams to blind the driver and gunner. Projected plans call for these teams to use frangible hydro cyanic acid grenades against vision ports. Molotov Cocktails are to be thrown into the engine compartment to set it afire, and riflemen are to fire at vision slits and any other vulnerable part.
CLOSE IN ATTACK OBJECTIVES
FRANGIBLE H C N GRENADE
FRANGIBLE SMOKE GRENADE
FRANGIBLE INCENDIARY GRENADE (MOLOTOV COCKTAIL)
TYPE 93 ANTI-TANK MINE ATTACHED TO POLE
HAND GRENADE CLUSTER
YARDSTICK MINE
HAND GRENADES WITH HOOKS TYPE 93 ATTACHED ANTI-TANK MINE TYPE 99 MAGNETIC MINE
This illustrates one Japanese conception of the points on an American tank vulnerable to close in anti-tank attack weapons.
RAGE 25 (7> m CHARACTERISTICS OF JAPANESE ANTI TANK MINES ro -1
Pressure1- AP* TYPE 93 TAPEfciEASURE (a) In fields 6 3/4" Diameter Picric acid or shear wire - 30 MINE (b) Cta poles 1 3/4" Thick Dull brown 3 lbs* 2 lbs. 50/50 TNT and lbs., AT shear Instantaneous Cyclonite. wire - 250 lbs.
(a) In fields 36" long; Pressure anti YARDSTICK MINE (b) Oh poles . Oval cross sec- dive drab 10 lbs. 8 oss. 6 lbs. Picric Acid tank shear wire Instantaneous ti on H/5"30l/3" 336 pounds.
50 lbs. pressure 8« Diameter any place on hem DUTCH MUSHROOI TYPE In fields 3kn Thick CQLive drab 94 lbs. 5i lbs. Cast TNT ispherical cover Instantaneous
TYPE 3 MODEL A (a) In fields Diameter Light tan Type 88 or mix Pressure - 22 lbs TEKRA-COTTA (SMALL) (b) As AP mine* 3tw Thick (pottery) 4i lbs. ture of TNT and Pull of 5 lbs. Instantaneous LAND MINE (c) As booby trsp ammonium nitrate
TYPE 3 MODEL A (a) In fields 10$-" Diameter Light tan TERRA-COTTA (LARGE) (b) As AP mine* Thick (pottery) 10£ lbs. 64- lbs. SAME SAME Instantaneous LAND MINE (c) As booby trqp
(a) In fields TYPE 3 MODEL B 7 l/8" Square WOODEN LAND MINE (b) As AP mine* Natural Pine 6 lbs. 44" lbs. Type 88 SAME Instantaneous (c) As booby trep 4 7/8" Deep (a) In fields HEMISPHERIC AL JXHI (b) In shallow 20N Diameter 60* TNT 2 leaden ANTI-BOAT MINE water (base); 10" high Black 110 lbs. 464 lbs. AO% TNA chemical horns Instantaneous (c) As AB mine
CONICAL J-XVI 14n Diameter 1 leaden SAME Black 70 lbs. 22 lbs* BEACH MINE (base); 12" high SAME chemical horn Instantaneous
Hand placed 4 3/4" Diameter Picric Acid or TYPE 99 MAGNETIC MINE or thrown li" Thick Khaki 2 5/8 lbs. l£ lbs. TNT & Cyclonite Percussion type 10 Seconds
TYPE 3 MODEL A CONICAL 4 3/8" Diameter 50% TNT Hand thrown HAND IHRfiHN MINE (base);6 3/4rtlon| Olive Drab 2 3/4 lbs. 1 7/8 lbs. 50>6 Cyclonite All-ways action Instantaneous (Large)
TYPE 3 MCDEL B CONICAL 4" Diam. (base); HAND THROWN MINE Hand thrown Bright Yellow 1 5/8 lbs.. 1 3/8 lbs. Picric Acid All-ways action Instantaneous 6" Long
2 KG CONICAL Hand thrown HAND THROWN MINE or placed Brown leather 44 lbs. approx. Percussion type 10 Seconds
5 KG HIMISPHERICAL Hand placed by ARM® PIERCING MINE pole or rope Black 11 lbs. approx. Percussion type 10 Seconds
Shoved against 8" Diam. (base) LUNGE MINE Black tank ll£" long 15 lbs. 7 lbs. Crude TNT Percussion typej Instantaneous
•ANTI-PERSONNEL TYPE 88 EXPLOSIVE* Ammonium perc hiorate 6658, Silicon carbide 16$, Wood pulp 12%, Crude oil 6%. ENEMY TABULATION OF EFFECTIVENESS OF ANTITANK MINES THICK.NESS OF ARkO:ft ANTI-TANK V&APONS \" 1 REMARKS 0 20*n*«« i | 60,mm OOnm IDOmht 150mm 100 I | 1 I 1 j Type 3 (Model A) 1 Effective against sides and rear 1 1 1 of M3 and M4 medium tanks. Hand Thrown Mine 1 1 1. 1 1 Type 3 (Model B) 1 ! i | 1 Hand Thrown Mine 1 ! 1 1 ' 1 SAME (called 1 kg Con 1 1 1 ical Mine. 1 1 | i | 1 1 1 1 | 2 Kg Conical AP . 1 i | | SAME Mine 1 1 ' i 1 1 1 1 t 1 ' i i | 1 5 Kg Hemispherical 1 i *J SAME (AP) Mine i i 1 i i i i • Explosive Charge3kg i 1 1 i i 5 kg 1 (Also called bundled charge) i 1 16 kg i i 30 kg i | -I 1 p 1 1 1 1 Type 2. Hollow- 1 1 1 (Probably for 40 mm grenade) Charge Rifle 1 i i Grenade 1 | 1 1 1 1 i Ii 1 i 1 It is necessary to use a cluster \ 1 1 1 Type 99 Magnetic 1 i i of 6 mines against 60 mm of steel i wmfci i AP Mine i | 1 plate. i i 1 i i 1 i 1 I i ' 1 Two mines will sever track of Type 93 Tapemeasure ' I 1 1 light tank; four mines will sever Mine i 1 1 track of medium tank. i i 1 i i i l 1 i i i | i 1 1 Yardstick Mine 1 i i Severs track of medium tank. 1 | • 1 1 l 1 i t i 1 1 i | i i Type 3 (Terra- 1 i 1 Will sever track of (Japanese) i i 1 i i Type 89 Medium Tank. Cotta) Land Mine i i 1 I ! 1 i i Based on captured documents• AT Guns
The Japs realize that their smaller caliber antitank guns including 13, 20, and 25 mm weapons are not effective at long ranges against heavy armor and are plac ing more emphasis on larger antitank guns.
Hollow-charge ammunition has been reported or encountered from the 57 mm Tank Gun, Type 92 70 mm Battalion Howitzer, Types 38 and 95 Field Guns, Types 41 and 94 fountain Guns, and for 10 cm Howitzers. It is likely that these weapons were so supplied, however, only for close-in defense against tanks or for emergency firing, when no other antitank weapons were available. If a tank was hit with this ammuni tion, considerable damage would undoubtedly result, but a gun's effectiveness must also be measured by its capability of hitting a moving or pin-point target. Low muzzle velocity, high trajectory, and slow traverse of the pieces measurably de crease their accuracy against tanks.
The Japanese have conducted firing tests with high explosive shells fired from their standard artillery pieces. They concluded that only weapons larger than 75 mm would be effective against tanks, and then only a direct hit or a very near miss would knock out the tank. A 15 cm howitzer shell must land within one yard of a tank, and a 10 cm howitzer shell within one foot.
The 47 mm has replaced the 37 mm AT gun in many units, and many of their Model 97 medium tanks have been modified to take a 47 mm gun in the turret. The Type 94 37 mm AT gun however has been frequently encountered, and it is likely that it will continue to be in the future. This weapon has a muzzle velocity of 2,300 feet per second and a maximum range of 2,500 yards. The effective range is probably about 700 yards. It is capable of firing AP or HE ammunition at a sus tained rate of fire of 12 rounds per minute. In firing tests with armor piercing ammunition at a range of 120 yards, it penetrated 14/5 inches of rolled armor plate. Other 37 mm AT guns including the Type 11 and Type 97 are known, but the Type 94 has been the most frequently encountered.
PAGE 28 Type 93 13 mm Machine Gun, Type 97 20 mm Antitank Gun. rnrnrnm | 1
HnH
Type 98 AA/AT Gun. Small caliber antitank weapons
PAGE 29 Type 94 75 ram Mountain Gun. Type 92 70 mm Battalion Howitzer.
Type 95 75 ram Field Gun. A,
Type 91 105 mm Howitze
The Japs are reported to have H.E.A.T (hollow charge) ammunition for these guns for use against tanks, but they will probably be used in a supporting role in AT defenses or for their own defense in case of a tank break-through. (For more de tailed information about these and preceeding guns mentioned in this report see CINCPAC-CINCPOA Bulletin 26-45, Japanese Artillery Weapons and CINCPAC-CINCPOA Bulletin 55-45, Japanese Infantry Vtieapons).
PAGE 30 The Model 1 47 mm AT Gun has become the mainstay of Japanese antitank defenses. It is a highly mobile, easily handled, low trajectory, high muzzle velocity weapon. The enemy reports that at a range of 1,000 yards with armor piercing ammunition, this gun can penetrate over 2 inches of armor plate. Although its performance against face hardened armor has not rated high in the past, recent encounters with this gun show it will penetrate the side and turret armor of U. S. medium tanks at ranges up to 1,000 yards, if the angle of iirpact is normal. The maximum range is approximately 3,700 yards; effective range is probably over 1,000 yards. This weapon may be fired at a sustained rate of 12 to 14 rounds per minute.
The Type 90 75 mm field gun, although primarily an artillery piece, was used as an antitank gun in the Philippines and on Iwo Jima. It has become the enemy1s most effective long-range antitank weapon.
High explosive armor piercing ammunition has been recovered for this weapon, and with this the Japanese claim penetration of almost 4 inches of armor at short ranges.
It has a muzzle velocity of over 2,200 feet per second, the highest of any of their field artillery weapons. When equipped with rubber tires, it becomes a highly mobile antitank gun. Its weight is only 3,080 pounds. A trained crew can deliver fire at a sustained rate of 10-12 rounds per minute. The gun has a maximum range of 15,000 yards and an effective range against tanks of probably over 2,000 vards.
The rubber tires for Type 1 47 mm antitank gun and Type 90 75 mm field gun have been described erroneously in the past.- Examination of a tire from the Type 90 reveals that the outer tire is similar to an ordinary automobile tire, but instead of an air-filled inner tube, the interior of the tire is filled with sponge rubber which has small air spaces to provide more elasticity.
Shown at left is Type 90 75 mm Field Gun
PAGE 31 Im
CM ENEMY TABULATION OF EFFECTIVENESS OF ANTITANK GUNS
TYHS THICKIESS OF ARIJ01i HEKARKS '.EAPON OF r 4 SHELL 0 2.Dmh> ] 40 tain ffj) mm f »5 Indicates a round from a Type 90 75 mm Indicates a round fired from a Type 1 47 mm Gun at the range in meters shown preceeding it. Indicates a round fired from a Type 94 37 mm <35® Gun at the range in meters shown preceeding it. In the figures 15/21° etc., the numerator indicates the thickness of the armor in millimeters (15 mm); the denominator indicates the angle formed with the horizontal by that part of the tank (21°). CS stands for curved surface. All rounds are armor piercing except as otherwise indicated. (25.4 mm equals 1 inch). (100 meters equals 110 yards approx.) For the TypB 1 47 mm AT Gun the maximum range noted is 1800 meters for the Type 94 37 mm it is 1000 meters except for firing against the gun of the light tank. The greatest range prescribed for the Type 90 75 mm Field Gun against medium tanks is 2500 meters and against light tanks is 3000 meters. In many instances in the Philippines, the Japs held the fire of their 37 mm and 47 mm AT guns until our tanks were within 100 or 200 y^rds, and within 500 yards range of the Type 90 75 mm Field Gun. GUN PORT (85 +39) FRMl&ttlE INCENDIKW GRENM>E REMl SOREIkCE 80TTOJ* PLATES 23-13 U. S. MEDIUM TANK IUKEIY r- ™ REAR 5URfKCE-|^ 1500* Wow STILL \I800)A CHURCHILL IHFAIJTRY TANK 5 Om oj o> COen 0o ooo^ U.S. LIGHT TANK M3 $ « UNCLASS1FIE UNCLASSIFIED