Tuesday, March 31, 2015

Japanese Armour

In the Japanese language the word for battle, sen, has been combined with the word for wagon, sha, to form sensha, a tank. Japanese interest in armoured fighting vehicles can be traced back to the 1920s when the British firm of Vickers persuaded the Japanese War Ministry to buy one of the Medium C tanks which Vickers salesmen were endeavouring to sell to a number of foreign powers. In fact the Japanese had already embarked on the building of a heavy tank, but when their designers ran into trouble from lack of experience they decided to adapt foreign designs to their requirements. 

Thus in 1929 when Japan started producing her own tanks they were based on early models of the French Renault M1917, the Vickers Medium C, and the Carden-Loyd light tank Mark VI. For the most part the Japanese models closely followed the design of the originals. The Type 89A which appeared in 1929, for example, bore a strong resemblance to the original Mark C prototype which Vickers had supplied to Japan in response to their order for a Medium C three years previously. However, the Type 89A had thicker armour, only two machine guns instead of four, and a crew of four instead or the five needed in the Mark C. The Japanese tank also had a stronger suspension, but this and the additional weight of the armour resulted in a slower speed. In effect the Japanese had converted a fast light tank into an infantry support vehicle. The decision to do so was to be reflected in subsequent Japanese armoured policy up to 1945. Tanks were generally regarded as subordinate to the traditional arms, and not as an arm of decision in their own right.

In 1932 the experimental Type 89A was followed by the Type 92, a so-called 'heavy' tank (of 26 tons) whose 34 bogie wheels gave it the appearance of a giant man-made centipede. The Type 92 did not prove successful and the Japanese turned to the design of lighter armoured fighting vehicles more in keeping with their maritime strategy aimed at weaker opponents.

The first Japanese tankette came into service in 1932, and was clearly a development of the Garden Loyd series of weapon carriers. Like the thin-skinned light tank T95 which appeared in quantity three years later, the tankette was used with success against the Chinese in the Sino-Japanese war. The Chinese had no effective equipment with which to counter the Japanese armour and the fact that they frequently conceded a battle when Japanese tankettes and Type 95s appeared undoubtedly distorted Japanese views of armoured fighting vehicles. While the development of tanks and tank tactics was accelerating in Europe, Japanese technology made little advance, probably because the theatres in which they expected to fight were not suited to uninhibited tank battles. Shortly before the war in Europe, however, Japan did introduce a new tank which owed much to her own designers. This was the medium Type 97, known also as the Chi-Ha, which went into service in 1942. Developed from the Type 95, the Chi-Ha was eventually developed to carry a variety of armaments, including in one version a 150mm gun, and in another, a 300mm mortar.

By European standards the armour of the Japanese tanks was thin, but the main armament was comparable with equivalent British and American tanks so far as calibre and weight of projectile was concerned.

General Characteristics
Classification: Japanese tanks were divided into:
Tankettes 3 to 4.5 tons
Light Tanks up to 10 tons
Medium 10 to 20 tons
Heavy over 20 tons
Tanks were named after the manufacturer, and — like their other weapons and military stores — numbered by the Japanese calendar year, dates being taken from 660 BC (which was their year 00). Thus the European equivalent of a year date is found by subtracting 660.  
Turrets: were all round or oval.
Armament: In some models a machine gun was mounted in the back plate of the turret. Special machine gun compartments were often built out of the superstructure. Machine guns were seldom, if ever, mounted coaxially with the main armament.
Armour: The most heavily armoured Japanese tank of World War II was the obsolescent M2595, 27 ton heavy tank, with 35mm (1.38in) armour on the front.
This was inadequate in a tank of this weight. The Japanese generally used rolled armour with welded and riveted joints, both types of joint being commonly found in the same tank. The use of curved plates was a common feature.
Suspension: In the tankette, and the latest light and medium tanks, the Japanese used modified Carden-Loyd suspension in which the weight of the tank was supported by horizontal compression springs arranged inside tubular protective casings on each side of the hull between the bogie wheels and return rollers.
Speed: Maximum speeds were not high, but the power-weight ratios (25 for the light tank) resulted in good cross-country speeds.
Lightness: The Japanese have emphasised lightness, and track pressures were low, giving an important advantage when travelling over soft ground.
Insulation: Woven asbestos heat insulation was placed inside the hull and turret of the tankette and light tank.
Engines: The Japanese used air-cooled diesel engines.
Accommodation: By European standards crew accommodation was cramped.

Japanese Armour WWII

Some Chinese warlords and the Guomindang had a hodgepodge of tanks imported during the 1920s, notably several dozen Renault FT-17s (Model 1918). During the early 1930s, China acquired Carden Lloyd Mk VI patrol tanks, about 20 Vickers 6-ton light tanks, and several dozen Vickers medium tanks, as well as Italian L. 3/35 tankettes and German Pz-1As. The Guomindang acquired Soviet tanks and armored cars in 1938, mainly T-26s, BA-10s, and BA-20s. The United States provided some Lend-Lease Shermans to China from 1944 to 1945. 

The Japanese were only marginally better off than the Chinese in terms of tank design, but they had many more tanks. Most were light or tankette types, copies of early French Renaults or British Vickers models. The standard Japanese tank from 1932 was the 10-ton Mitsubishi Type-89 Chi-Ro medium, which was basically an infantry assault vehicle mounting a small 57 mm gun. It was produced until 1942. A few Type-95 "heavy" tanks were built. The first Mitsubishi Type-97 Chi-Ha medium tank rolled off the assembly line in 1937. It weighed under 16 tons and mounted a small 57 mm gun. It became the standard Japanese model of the war. The Japanese Army also used its tanks differently. It deployed armor in "tank groups" (sensha dan) of three or more regiments of 80 tanks each. Japanese doctrine dictated that all armor act in an infantry support role, until the Japanese experienced what massed Red Army tank divisions could do at Nomonhan in 1939. It still took Japan until 1943 to deploy its first true armored division, which was sent to Manchuria and saw little to no action. Shortages of all critical materials meant that Japan only produced five light tanks in 1945. Despite improvements to Japanese tanks and doctrine, Soviet armor again rolled over the Japanese during the Manchurian offensive operation (August 1945). 

The major Western Allied nations fighting in Asia used the same models built in abundance to fight Italy and Germany in Africa and Europe. The topography of Southeast Asia and the South Pacific was not generally conducive to armored warfare. The central plains of Okinawa saw more tanks used by both sides than in any other battle outside China.

With the exception of the remarkable Soviet T-34, Allied tanks, on a vehicle for vehicle basis, were generally inferior to German tanks. In the Pacific theater, however, the Allies, particularly the Americans, had the advantage. The Japanese militarists had created a formidable force in the Imperial Army, but they had largely neglected armor. As a result, they fielded only two major types of tanks, both outclassed by the American Sherman. The lack of emphasis on the tank is understandable, since the Japanese correctly envisioned fighting on Pacific jungle islands, not the open spaces of the European battlegrounds. What tank designs the military did order were light to medium, capable of being readily sealifted and landed. 

Type 95 light tank (Ha-Go).
The Type 95 light tank, the Ha-Go, was developed in 1933 by Mitsubishi and was used throughout World War II. Light and durable, it could be readily landed during amphibious operations, and it performed well in the absence of roads and across marshy or monsoon- soaked ground. Its air-cooled, six-cylinder diesel performed well in Northern Manchuria as well as the Pacific jungles. Crewed by three or four, its small turret accommodated only a single man, so that, in addition to directing the driver, the commander had to load, aim, and fire the main 37-mm gun. Armor plating was very light, making the Type 95 extremely vulnerable to fire of all kinds. Although the Type 95 was a reasonable match for a U. S. M3 Stuart, it was readily outclassed by the Sherman.

Type 97 medium tank (Chi-Ha).
The Type 97 medium tank, called the Chi-Ha, went into production in 1937, just in time for use in the Sino- Japanese War. Heavier than the Type 95, it was a medium tank of reasonably advanced design, but it was too heavy for the jungle terrain of the Pacific. It therefore did not enjoy great success in that principal theater of the Pacific war. Nevertheless, Mitsubishi produced about 3,000 of the vehicles mounting a 57-mm main gun as well as specialized versions used as tank recovery vehicles, flail mine clearers, bridge layers, and self-propelled gun mounts for antiaircraft guns. Very late in the war, the Imperial Navy even installed a 120-mm gun on some Type 97s.

List of Japanese armored divisions of the Imperial Japanese Army. During World War II, the IJA only organized four divisions, these were:

Panzer Development I

Though there had been no significant tank-versus-tank engagements during the Polish campaign, German planners were aware that against the French and British, they would face superior numbers, better armed and armored vehicles, and not least stronger antitank defenses. As the Wehrmacht began the process of deploying westward, the armored force underwent a major restructuring.

First to go were the light divisions. Field experience confirmed the prewar decision to concert them to panzer formations. While they had generally performed well enough on the move, lack of tanks proved a major handicap whenever it came to fighting. Adding a company of mediums was unlikely to remedy the problem. Instead they were renumbered as the 6th through the 9th Panzer Divisions and given a two-battalion tank regiment (a single battalion in the case of the 9th). Increased production of Panzer IIIs and IVs resulted in new tables of organization as well. In February 1940 every tank battalion was authorized two light companies, each with two platoons of Panzer IIs and two of Panzer IIIs, and a third “medium” company with a platoon of five Panzer IIs and two platoons totaling seven Panzer IVs; more larger tanks would be issued as they arrived.

That was the theory. In fact, the new tanks trickled in during the winter and spring of 1940. The gap was filled in part by delivery of the 38(t). Around a hundred each went to the 7th and 8th Panzer Divisions (the 6th had the older 35(t)); the other seven divisions had German vehicles, including a significant number of Panzer Is—around a hundred in the 3rd, 4th, and 5th. The next campaign would still be a light tank operation, with all the accompanying implications for better and worse.

In one respect the tanks would be even lighter than desired. The Panzer IIIs coming into the battalions were models E and F, with 30mm of frontal armor and the highest standard of reliability in the armored force. The gun, however, was the original 37mm. The Weapons Office and the armored force alike had originally wanted a heavier piece. A 50mm/42-caliber gun was available; the tank’s turret and turret ring had even been designed to mount larger weapons, but retooling would reduce production at a time when every tank counted. Only a few of the up-gunned versions would see action in the western campaign.

Experience in Poland indicated that the motorized divisions were too large to be controlled in mobile operations. Each shed a regiment, usually transferred to a panzer division organically short of infantry. The Cavalry Rifle Regiments and the reconnaissance formations of the former light divisions were reorganized to panzer division standards with some anomalies—including the troopers’ pride that kept them wearing cavalry yellow branch insignia instead of donning infantry white. Armored half-tracks remained part of Heine’s “airy empire of dreams” for all except a few companies in the 1st, 2nd, and 3rd Panzer Divisions—the privilege of seniority.

As long as the infantry rode trucks, battle group system or no, they would be thrown sufficiently on their own resources to make organic support weapons vital: medium mortars, 37mm light infantry guns, 37mm antitank guns. In contrast to the foot-marching infantry, these were usually assigned to battalions. That in turn gave regimental headquarters more time to train in handling combined-arms formations, as opposed to using attached tanks as generic close support. The rifle companies and battalions, for their parts, intensified assault training, working independently and with the divisional pioneers to break the way for the tanks and then keep pace with them as they advanced.

A few other mobile formations existed as well. Two battalions of Panzer IIs converted to flamethrowers were authorized in the spring of 1940. The 40th Panzer Battalion for Special Purposes was organized with three companies of Panzer Is and IIs and a few experimental types for the invasion of Denmark and Norway. A two-regiment motorized brigade participated in the Danish phase of the operation. Far more significant was the appearance of the Grossdeutschland Regiment. Its ancestor was the Berlin Security Battalion, originally formed under Weimar to safeguard the government and showcase the Reichswehr. In 1937 it was expanded to regimental strength. Recruited, like the former Prussian Guard, throughout the Reich, it was considered a corps d’elite and in 1940 it included four battalions. Three were standard motorized infantry. The 4th, prefiguring later developments in the motorized infantry, was a support battalion with an infantry gun company, an antitank company, and something entirely new: an assault gun battery of six self-propelled 75mm mounts.

The assault gun was a product of exigency: a substitute for the heavy tanks projected in the 1930s for direct infantry support; and a consequence of branch rivalry in the German army. Had rearmament progressed in the systematic fashion envisaged by the General Staff and the High Command, or had Hitler adjusted his diplomatic offensive more closely to Germany’s military capacity, assault guns might well never have existed. Their institutional patron was the artillery. Responding to the nascent armored force’s call for tanks to be concentrated under its command, Germany’s gunners argued that infantry support would inevitably suffer. Experience indicated that weapons in a different branch- of-service chimney were all too likely to be totally elsewhere when needed.

During World War I, the artillery had responded by forming specialized “infantry gun batteries,” armed with modified field guns—an approach unique to the German army. There had never been enough of them, and in the 1920s the Reichswehr had developed two purpose-designed infantry guns, one 75mm and the other 150mm—the same caliber as the standard medium howitzer. Introduced in regimental gun companies, they were useful but disproportionately vulnerable, especially at close range. Their crews, moreover, wore infantry-branch white, and the cannon cockers saw themselves being relegated to third place in the combat arms pecking order.

In 1935, Erich von Manstein, newly appointed head of the General Staff ’s Operations Section, prepared a memo consolidating previous discussions and recommending the development of a self-propelled “assault gun” to work directly with the infantry, with each division having its own battalion. What the gunners described, and what the Weapons Office turned into a development contract in 1936, was to a degree a throwback to the original Allied tanks of World War I: a vehicle with a low silhouette for concealment “not to exceed the height of a standing man,” all- round armor protection, and a 75mm gun with both high-explosive and armor-piercing capacity. Putting those requirements together made a turret impossible; the gun would instead be mounted in a fixed superstructure with a limited traverse of 30 degrees. Initially, as in the later US tank destroyers, the top was open to facilitate the observation considered necessary for tactical effectiveness at infantry ranges. Before going into production, however, the vehicle was given a roof and a panoramic sight enabling it to employ indirect fire. After all, assault guns were artillery weapons.

Guderian, the armored force’s designated pit bull, argued that the concept was a mistake. Turreted tanks could do anything assault guns could do; the reverse was not the case. A subtext amounting to a main text was that the projected assault gun would use the chassis of the Mark III tank and the gun intended for the Panzer IV. Guderian and his tanker colleagues were not placated by projections indicating that rising production would avert serious competition for chassis. A disproportionate number of officers in senior army appointments had begun their careers in the artillery—Fritsch, Beck, and Halder, among others. It has been suggested that a “gunner mafia” thwarted Guderian out of branch rivalry. More to the point was the fact that the light tanks that were expected to become surplus as the IIIs and IVs entered service were too small and fragile to carry a three-inch gun even in a hull mounting, while the artillerymen wanted every active infantry division to have its assault gun battalion by the fall of 1939.

In practice, assault guns never became a high-priority item. The first soft-steel experimental models were not completed until 1938. The first production run was only 30, and those were not delivered until May 1940. Only a half dozen six-gun batteries saw action in France. Later orders placed in early 1940 were for only 120 vehicles—hardly evidence of either branch or institutional commitment to the concept. Not until the Sturmgeschütz III proved its worth beyond question did the contracts expand and the assault gun begin to take its place beside the panzers in Wehrmacht history and military lore.

Light tank chassis were nevertheless good for something. The towed antitank gun was still considered satisfactory as the backbone of antitank defense. The army’s offensive mind-set, however, encouraged active defense to the point where the initial title of Panzer Abwehr (tank defense) was changed prewar to Panzerjäger (tank hunter). The 37mm gun was easily handled, but against the up-armored tanks coming into service, its days were numbered. The more powerful designs on the drawing boards were also significantly heavier. But the Czech army had possessed a very effective 47mm antitank gun and the armored force had an increasing number of Panzer Is becoming surplus to requirements. Remove the German turret, mount the Czech gun behind a three-sided shield, and the result was the first tracked, armored antitank gun to enter service. The design was patchwork and its numbers were small, but as with the assault gun, its relative success in 1940 made the 47mm Panzer I combination the first in a long line of similar improvisations in all armies.

In the interim between the fall of Poland and the attack on France, the armored force confronted another kind of technological problem. How best could the commander of a mobile formation built around the internal- combustion engine be at the critical point of a battle while at the same time continuing to command his whole force effectively? The panzer division included an “armored radio company,” but its vehicles were as a rule attached to division and brigade headquarters. Events in Poland had demonstrated the practical limits of radio communication under field conditions. “Leading from the front” invited the dispersion of effort as commanders seeking to exploit presumed opportunities wound up directing isolated actions that eventually devolved to skirmishes with limited tactical results. Guderian’s familiar mantra “klotzen, nicht kleckern” (“slug, don’t fumble; keep focused on an objective”) was sound enough. The problem was implementation.

Erwin Rommel, newly appointed commander of the freshly minted 7th Panzer Division, addressed the problem by developing a mobile headquarters based on an electronic command system mounted in a cross-country vehicle: a network of radios allowing him to contact both subordinate formations and his own main headquarters. He sought as well to develop a common way of doing things—not as a straitjacket, but rather as a framework for structuring the behavior of subordinates in the constant emergency that was the modern mobile battlefield. Commanders at all levels were to exercise independent judgment, with the division commander using his sense of the battle and the information provided by his headquarters to select points of intervention, ideally to refine and complete the efforts of the men on the spot.

Rommel made clear to his senior staff officers that he depended essentially on them to process and evaluate information in his absence, and to act on it, should that seem necessary. By later American standards, German divisions had small headquarters whose officers were relatively low ranking. That reflected exigency more than principle; the army after 1933 was never able to keep pace with its own expanding need for troop staff officers. The often-praised “lean and mean” German structure meant everyone worked constantly. Vital information could be overlooked by busy men. Fatigue and stress led to errors in judgment and to problems of communication as tired, frustrated alpha-male subordinates snapped pointlessly at each other. Especially in a mobile division, success depended heavily on a commanding general willing to support the decisions of even junior staff officers in whose ability, toughness, and loyalty he had confidence.

There was only one Rommel, who in the 1940 campaign would deliver arguably the most outstanding division-level command performance in modern military history. But in every panzer and motorized division, men with similar perspectives were assuming senior posts. Friedrich Kirchner of 1st Panzer Division, the 6th’s Franz Kempf, the 10th’s Friedrich Schaal, and their counterparts were not water-walkers. But they were solid professionals, able to get the best out of subordinates. Some began as gunners, some as infantrymen, and some wearing cavalry yellow. What they had in common were high learning curves, fingertip situational awareness, and emotional hardness unmatched even in the Red Army. The combination would prove consistently formidable, no matter the operational considerations.

Fighting the French had also indicated that in armored war, quality was at least as important a force multiplier as numbers. Survivability was important both to sustainability and morale. The vulnerable Panzer Is and IIs were being replaced with the more formidable Panzer III coming off the Reich’s production lines. The repeatedly demonstrated shortcomings of the 37mm gun as a main armament led to its replacement in the G version by a 50mm gun whose 42-caliber barrel made it a rough counterpart of the 75mm gun mounted on the early versions of the US Sherman—that is to say, a general-purpose weapon useful in supporting infantry, effective against tanks, but not a real tank-killer. About 450 of this version were produced by February 1941, alongside 300 of an up-armored Model H. A number of older Panzer IIIs were also rearmed with the 50mm gun—a tribute to the generous design of the turret ring. The Panzer IV had been satisfactory overall; its E and F versions were distinguished primarily by increased side and frontal armor.