A self-propelled anti-tank gun is, simply put, a tank gun with its own mobility. Generally, it features a medium-performance chassis, light armor protection, and a high-powered tank gun capable of destroying enemy armor at standard combat ranges.

A tank destroyer, by WWII-era standards, combines a turretless medium-performance tank chassis, a high-powered gun mounted at the front of the hull, and thick, fully enclosed armor.

Compared to their parent tank, both tank destroyers and self-propelled anti-tank guns carry more powerful guns. The distinction between the two is often blurred — their roles frequently overlap. Generally, the fully enclosed, heavy-armor variants are called tank destroyers, while those with exposed crews and thin armor are called self-propelled anti-tank guns. Exceptions exist, however: American M10 and M36 tank destroyers, despite their name, had frighteningly thin turret armor.

Unlike the Soviet Union and Germany — which fielded vast numbers of tank destroyers and self-propelled anti-tank guns — China's development in this area, though extremely early, saw lower production numbers and less institutional emphasis. The primary reason was that on the Asian front, Chinese tanks maintained overwhelming superiority over British and American armor. China, rich in tungsten, could lavishly employ tungsten alloy armor-piercing rounds to bully its opponents: "If all else fails, just blast them with gold coin rounds." Meanwhile, infantry deployed abundant portable anti-tank weapons. With anti-tank pressure low, the main demand for self-propelled guns was not anti-armor but rather high-explosive support against enemy infantry. Chinese armored divisions' self-propelled artillery therefore consisted mainly of large-caliber howitzers.

Unlike the American approach — "tanks are for killing infantry, tank destroyers are for killing tanks" — in China, the view that "the best anti-tank weapon is a more advanced tank" was always mainstream. The Panda's and Cloud Leopard's outstanding performance had long established great psychological confidence among armored troops. Although turretless tank destroyers or self-propelled guns packed more powerful weapons, they faced severe operational limitations. Combined with opponents deemed insufficiently formidable — "there's nothing on their side that our tanks can't handle" — the consensus that "bigger-caliber anti-tank guns are pure overkill" persisted in the military for years.

From the perspective of front-line tankers and infantrymen, what truly gave them headaches were the powerful British and American air forces and the annoyingly ubiquitous bazooka rockets. Against air strikes or heavy artillery bombardment, the semi-open, tissue-thin armor of self-propelled anti-tank guns was terrible. Fully enclosed tank destroyers fared somewhat better, but the inability to rotate the turret always felt "uncomfortable" in practice. "Since there's nothing on the ground our tanks can't deal with, why do we need these stiff-necked big things?"

China's tank destroyer and self-propelled anti-tank gun development was pioneered by three early designs. In the late 1920s, when the Fox tank was entering service and 75mm field guns were being retired, the Chinese military's idea of mounting old WWI field guns on Fox tank chassis produced the first self-propelled gun concept.

Early Fox tank-mounted trials led to the "Marmot" — an open-topped self-propelled gun using a Fox tank chassis with the turret removed and a WWI-era 75mm/L27 field gun mounted atop. Meanwhile, an alternative proposal sought to install a 47mm/L45 gun in the Fox using a turretless casemate layout. However, during anti-armor testing, while the 47mm/L45's armor piercing far exceeded the Fox's 37mm, the Marmot — despite using an outdated WWI gun — had the inherent advantage of 75mm caliber: superior armor penetration and substantially more powerful HE shells. Without question, the Fox chassis-based 47mm self-propelled anti-tank gun was eliminated.

The design that ultimately prevailed came from an ordinary researcher's concept: remove the turret, open a port on the Fox tank's front hull at the radio position to the right of the driver's seat, and insert the 47mm tank gun through it. The interior layout was then adjusted to balance the hull. In appearance, this tank destroyer was practically a miniature Hetzer — exactly two meters tall (excluding the AA machine gun), low-profile, fully enclosed, with excellent concealment and respectable protection.

This design ultimately succeeded, becoming the first true tank destroyer, designated the "Foxhound." By late 1933, a battalion of 45 Fox tanks received the conversion. For close-range infantry defense, a 12.7mm machine gun was added to the upper rear hull for self-defense and anti-aircraft capability.

Production was low primarily because the extensive hull interior restructuring required factory overhaul, consuming considerable labor-hours for modest performance gain. Only one battalion was converted for exercise testing, given the economics.

The Foxhound was China's first-generation tank destroyer, and its ingenious gun-mounting design deeply influenced subsequent tank destroyer development in both China and Germany. The Marmot self-propelled gun could likewise be considered China's first self-propelled anti-tank gun. Both fought in the 1939 Southeast Asian war. The British Matilda I was their most troublesome opponent — "troublesome" because its 60mm armor was too thick for the Foxhound's 47mm gun, which could only penetrate the frontal armor within 200 meters. But "not a threat" because the Matilda I was armed only with a machine gun and couldn't penetrate the Foxhound's armor under any circumstances.

The Marmot performed much better against armor. Its WWI-era gun, though "old," proved more effective against the Matilda I than the 47mm anti-tank gun. The only issue was the Marmot's weak self-protection — extremely vulnerable to enemy bombardment or infantry close assault. Southeast Asia's dense jungles, ideal for ambushes, exacerbated this weakness. A single grenade could destroy the entire crew when infantry closed in.

The second-generation tank destroyer was the "Wild Wolf" assault gun, developed on the Wolf tank chassis. Initially, the Foxhound layout was considered, but China had decided that the 76.2mm gun would be its future main tank armament. The new 76.2mm gun incorporated Soviet ZIS-3 technology. It wasn't changed to the universal 75mm caliber entirely due to Chen Ke's "big bore complex" — he couldn't tolerate Chinese tank calibers being smaller than anyone else's. There was also the factor of anticipated future world war.

As early as the late 1920s, the Chinese military had begun planning to retire its old German-pattern 75mm field guns. Mounting WWI-era guns on "obsolete" Fox tanks was merely "recycling waste."

After WWI, China imported large quantities of German 27-caliber 75mm field guns from France at barely above scrap-metal prices. Combined with domestic production, by 1925 the Chinese military had over 2,000 75mm field guns.

By 1928, with advances in metallurgy and having absorbed Soviet and German artillery advantages, China developed its first-generation field gun: the 75mm/L35 Thor field cannon. Light, powerful, long-ranged, and excellent in performance — but incompatible with old ammunition.

New equipment incompatible with old ammunition was every nation's greatest headache during weapons modernization. Two solutions existed: compromise new equipment performance to fit old ammo, or discard the old ammo and adopt new.

The debate was fierce, and the dispute ultimately reached Chen Ke for arbitration. His decision surprised everyone: cancel the 75mm caliber entirely and adopt the British 76.2mm bore.

Chen Ke's reasoning was simple: within a decade, a world war would inevitably erupt. At the scale of the last world war, Chinese artillery production would easily exceed 10,000 guns. Making tens of thousands of future guns accommodate ammunition designed for fewer than 3,000 obsolete pieces was idiotic.

This judgment was correct. Historically, the British committed the foolish expedient of using old ammunition in new guns to save money, paying a heavy price — the most famous example being the British 40mm "pom-pom" gun. Originally a classic weapon rivaling the Bofors, its barrel was shortened to "accommodate" vast stockpiles of WWI-era ammunition, drastically reducing anti-aircraft efficiency. The pom-pom's wretched performance contributed significantly to the sinking of HMS Prince of Wales.

Two reasons drove the change from 75mm to 76.2mm. First, Chen Ke's "big bore complex" — he didn't want to see his army's guns outmatched. Second, offensive pragmatism: both the Soviet Union and British Empire (which bordered China) used 76.2mm caliber. In wartime, captured enemy guns could be utilized with minimal modification; producing ammunition lines for them would also be much simpler. The 76.2mm HE was also slightly more powerful than 75mm.

As for the possibility of China being invaded and its weapons captured — this never worried Chen Ke. With national power rising steadily, he simply did not believe a China of 600 million people could lose the next world war.

Switching from 75mm to 76.2mm was major surgery for the Chinese Army. Over the following decade, old 75mm guns were gradually retired and replaced with new 76mm pieces.

In 1933, after Hitler's rise, Germany began rearmament. The economically devastated Germans were destitute. To strengthen Germany and cause more trouble for Britain and France, Chen Ke authorized selling 1,000 of the retired WWI field guns back to Germany at scrap prices — half gift, half sale. These guns played an important role in the Western European war years later.

The utterly impoverished German Army accepted these guns — which had originally been their own — with mixed emotions. The remaining German-made 75mm field guns in China were mostly provided as "Chairman Chen's generosity" in the same manner to red ally Japan. Chen Ke helped arm Japan so enthusiastically mainly because his transmigration had "bled Japan dry" too severely. If the 1933 German Army was poor enough to have only its underwear left, the Japanese Army had long been living the life of beggars without even underpants.

Post-revolutionization, Japan's economy had improved somewhat, but expecting impoverished Japan to simultaneously maintain naval and air force strength while investing more in its army was asking too much. These German guns matched the Japanese Army's existing systems perfectly — Japan's artillery had always followed the German pattern. With military budgets tight, their artillery units hadn't upgraded in over twenty years, making these WWI guns fully compatible with existing equipment.

By 1937, the Thor III field cannon — developed from the first-generation Thor — had its barrel lengthened to L/40. But installing the new 76.2mm/L40 tank gun in a Foxhound-type layout on the Wolf chassis encountered problems. The 76.2mm gun was too heavy; the single-side mounting caused excessive load on one side's road wheels, accelerating wear and making the vehicle difficult to drive. Balancing the weight would require major hull restructuring — uneconomical in terms of labor and cost. This approach was abandoned.

The final design choice was to use the same layout as its "German relative," the StuG III assault gun: remove the turret and mount the gun atop the hull. Compared to the Foxhound layout, this required fewer modification man-hours, though the hull was slightly heavier.

The second-generation "Wild Wolf" assault gun, using the Wolf chassis's casemate layout with a 76.2mm/L35 gun, served as the most important Chinese tank destroyer of the early war years before the Panda-based Hellhound appeared.

The third generation was the legendary Hellhound self-propelled anti-tank gun. Built on the Kangaroo chassis with its engine placed forward, the Hellhound mounted a 90mm/L50 anti-tank gun — the same gun as the Cloud Leopard's — in an open-topped rear fighting compartment. Its weight was only 19 tons, giving excellent mobility and acceleration. The 90mm gun's penetrating power was devastating. Combined with tungsten-core APDS "gold coin rounds," even the late-war Centurion and M26 were unwilling to test its full strike within 500 meters.

The Hellhound's most famous engagement occurred at the critical New Zealand city of Hamilton. An American armored division's 195 M4 tanks attacked Hamilton in force, encountering 20 Panda tanks (a reinforced company) and fewer than two battalions — 45 Hellhounds — in ambush within a valley outside the town. A fierce tank battle erupted.

The Pandas and Hellhounds performed a textbook-perfect combined arms demonstration: the Pandas deliberately exposed themselves on the forward line, drawing M4 fire with roaming shots, while the Hellhounds hid in pre-dug revetments, systematically igniting M4s one by one with their 90mm guns at 800 meters.

The battle lasted less than two hours. The American armored division's 195 tanks were virtually annihilated — only 15 tanks withdrew. Chinese losses were merely several Pandas and three Hellhounds.

After this battle, the Hellhound earned the name "Tank Killer" among armored troops.

After paying countless blood-prices, British and American tankers distilled two commandments regarding the Hellhound:

1. Facing Hellhounds head-on is suicide.

2. Even if you're the ultra-thick-skinned "Churchill" (infantry tank) or "Little Dumbo" (the most heavily armored M4 variant), don't assume you can always withstand the watchdog's bite.

3. The most effective method against Chairman Chen's watchdog is calling in air strikes or 155mm heavy artillery coverage.

When the Hellhound first appeared on the battlefield in 1941, it was a terrifying adversary for British and American tankers. By 1945 when the war ended, it was still regarded as "the most detestable, shameless rogue." That devastating 90mm anti-tank gun, combined with "gold coin rounds" (tungsten-core APDS), meant that even the late-war Centurion and M26 were unwilling to test being hit at 500 meters.

The Hellhound was acclaimed as the supreme masterpiece of China's tank destroyer/self-propelled anti-tank gun lineage. In retrospect, Western nations ranked the "Panda tank," "Cloud Leopard tank," and "Hellhound self-propelled anti-tank gun" as "Chairman Chen's Three Great Beasts."

The Hellhound's dominance led to slow development of other Chinese tank destroyer types after 1941 — even those developed saw minimal production.

The Wildcat tank destroyer — mounting a 50-caliber 76.2mm gun on a Panda chassis, referencing the Soviet SU-85's design — appeared in early 1942. Though lightweight at 24 tons with excellent mobility and protection, it was strongly opposed as a waste of Panda chassis. Only 185 were produced, typically assigned to rapid reaction forces for plugging gaps or distributed to infantry units.

After 1942, while the Hellhound excelled at anti-tank missions, British and American forces developed counter-tactics: at the first suspicion of Hellhounds ahead, they immediately called for heavy long-range artillery coverage. Compared to tough tanks, the Hellhound's hull was too thin — a single near-miss from a large-caliber HE shell could inflict devastating damage.

By 1942, front-line demand intensified for a sub-20-ton tank destroyer with medium protection. Neither Panda nor Cloud Leopard chassis were suitable for conversion to light tank destroyers.

The closest match was the Wild Wolf assault gun — a derivative of the long-retired Wolf tank that had been withdrawn from front-line service for not meeting universal chassis specification requirements. Its StuG III-like design, weighing 21 tons, marginally met front-line demands despite somewhat poor mobility.

The Kangaroo had originally derived from the Wolf. Under front-line pressure, Tianjin's Gao Bupang shamelessly "reversed" the Kangaroo's transmission — changing front-mounted to rear-mounted engines, backtracking on his own design philosophy. By now, however, the Kangaroo chassis was quite mature. The resulting chassis used 70% Kangaroo parts, 20% from the new "Red Panda" tank, and only 10% newly manufactured components. Armed with retired Panda 76mm/L40 guns, a 300-horsepower gasoline engine, 65mm/60° frontal armor, combat weight 18 tons. Gasoline rather than diesel was chosen because gasoline engines offered better startup characteristics and lower noise — more suitable for tank destroyer ambush tactics. This gasoline-engine design, like the Red Panda's, remained highly controversial among Chinese tankers.

This design — resembling the German Jagdpanzer IV and Hetzer — satisfied front-line demands for improved tank destroyer protection. But naming sparked another battle: Lin Pingzhi counter-attacked, claiming Gao Bupang had plagiarized his "Wild Wolf" design concept and demanding the vehicle be designated "Wild Wolf II." Gao Bupang insisted on "Cat-Eating Mouse." Their feud reached Chen Ke's arbitration once again. Chen Ke's final name for this light tank destroyer left both men equally disgruntled: "Mousetrap." This was the only piece of equipment in Chairman Chen's Zoo that wasn't named after an animal.

In practice, the Mousetrap's firepower was insufficient — far less devastating than the Hellhound's one-shot-kills. Despite excellent frontal protection, front-line evaluations were poor, and only 455 were produced before the line closed.

The story diverged overseas: Japan, having obtained the production license, mass-produced the Mousetrap — over 700 during WWII. Simple in structure, lightweight, mobile, with balanced protection and firepower, and extremely cost-effective, Japan produced another 200+ postwar for domestic use and export. It had the longest production lifespan of any WWII-era weapon.

Rumor later circulated that because it had only four pairs of road wheels — standing out conspicuously among the otherwise uniform "five-road-wheel" animals — Chairman Chen regarded it as a heretic and refused to admit it to the "Zoo's" pet roster.

Drawing on the Soviet SU-100 layout and their own front-line experience, the Spotted Leopard was WWII China's final tank destroyer. This type offered satisfactory firepower, protection, and mobility — China's only tank destroyer exceeding 30 tons during the war. But since nothing on the battlefield couldn't be handled by Cloud Leopards and Hellhounds, the Spotted Leopard was shelved as a technical reserve. Even the Centurion and M26 only "slightly" troubled Chinese armored forces. The Spotted Leopard's production was brought back to the agenda, but the war's end terminated the plan.

China's tank destroyer family had one more entertaining member. In 1940, at an Australian front-line tank overhaul depot, maintenance workers had a flash of inspiration: they mounted an old 76mm/L35 Thor field cannon at the rear hatch position of a turret-removed second-generation Kangaroo APC, cobbling together a tank destroyer. They vividly named it the "Hornet." Since the gun was mounted on its "behind," the vehicle fought facing away from the enemy. With the rear compartment occupied by the gun, crew entry/exit and ammunition resupply became troublesome, only possible through the original turret hatch on the hull roof.

This spontaneous front-line modification was unexpectedly successful and quickly became popular throughout the armored forces. Domestic factories, based on front-line feedback, soon produced standardized conversion kits. Because modification was easy, the variety of guns mounted on Kangaroo "behinds" could only be described as "chaotic" — besides the 76mm field gun, 105mm light howitzers, captured British and American light howitzers, and 57mm (six-pounder) anti-tank guns were all documented in field-conversion examples. The exact number of Kangaroos modified this way remains unknown. Interestingly, while after 1943 these "gun-on-the-butt" Hornets could be found in virtually every armored division on the front line, domestic production lines never formally authorized Hornet production. Every single "Hornet" was a front-line maintenance workshop improvisation.