The Fox tank was the replacement designed to succeed "Cat and Mouse."

Having absorbed the lessons and experiences exposed during the Cat and Mouse's service, the Fox was designed from the start around five key requirements: four-person crew, larger-diameter road wheels, sloped armor, diesel engine, and a larger-caliber tank gun.

To meet these goals, the design weight was raised to the ten-ton class, though actual design was done at a 20% redundancy margin — effectively a twelve-ton tank.

When the Fox tank finally emerged, its combat weight was twelve tons. Its main gun caliber was increased to 37mm, matching the Army's 37mm anti-aircraft gun caliber, with ammunition interchangeability.

The Fox had multiple improved variants, but the main gun caliber never changed. Total production reached 1,005 units, of which 220 secondhand Fox tanks were exported at "friendly" prices to Japan and Korea — those two "friendly" nations. Japan, by then "turned red" by Kita Ikki, even obtained a production license for the Fox.

For the first five years of the 1930s, China's armored forces followed a development path of small, rapid steps. With improving land border security, warming relations with the Soviet Union, and greatly reduced land defense pressure, military spending could be comprehensively shifted toward the Navy and Air Force. Thus the Army's tank fleet was not enormous. By 1935 — counting Kangaroo infantry fighting vehicles — the total number of tanks and armored vehicles across the entire military was maintained at only around 2,000. Even so, this figure was second only to the Soviet Union (which had built over 20,000 tanks before WWII), surpassing Britain and France for second place worldwide.

As for the Wolf tank — it was the product of the fifteen-ton tank program. Chinese production was lower than the Fox's, totaling only 608 units, with a 47mm gun. Its German "relative," however, surpassed 2,000 units. The main reason for the Wolf's limited Chinese production was Chen Ke's "big vehicle, big gun" philosophy and the early successful development of its "enlarged version."

The Germans, who had shared tank design experience with the Chinese, simply transplanted the Cat, Fox, and Wolf designs wholesale during Hitler's post-rise comprehensive rearmament — merely modifying the powerplant systems. For naming, the methodical Germans simply designated them Panzer I, Panzer II, and Panzer III. Panzer I was produced in small numbers for testing only. The Panzer II (Fox derivative) with its 37mm gun was produced in nearly a thousand units and became the backbone. As for the Panzer III, using a 47mm/L45 gun, it entered service a full year earlier than in the historical timeline. By the time Germany annexed the Sudetenland, nearly 500 had already been produced. The historical scene of German tankers rejecting the Panzer II and scrambling for Czech 38(t)s never came to pass.

The Wolf's German relative was also influenced by Chen Ke: the Wolf's 47mm caliber replaced the 50mm caliber of the other timeline, becoming the main gun for the Panzer III in Chen Ke's timeline. This happened to match the caliber of Czech-produced Škoda 47mm tank guns — in fact, this tank gun was a Chinese improvement on imported Czech Steyr armory technology, with the Chinese extending the barrel length from L/36 to L/45.

Although 47mm is three millimeters smaller than 50mm, consider what would have happened without Chen Ke's influence: in the original timeline, the Panzer III had only just begun mass production by the time the Poland campaign began in September 1939, armed with a pathetic 37mm gun. When attacking France, fewer than fifty Panzer IIIs in the entire German army had been upgunned to 50mm. The vast majority fought Britain and France's thick-skinned tanks with the contemptible 37mm — nicknamed the "door knocker" — at a qualitative disadvantage. Germany's brilliant Western Front victories were achieved entirely through the superior quality of German tank crews, not tank performance.

In China, the Wolf tank's fate resembled that of its German cousin the Panzer III. When the more advanced Panda and Cloud Leopard tanks entered service, some Wolves had their turrets removed and were converted into assault guns, or re-equipped with 105mm light howitzers to become China's first self-propelled guns. However, due to the Wolf's limited production numbers and to avoid burdening front-line logistics, apart from initial combat in the Southeast Asian campaign, existing front-line Wolf tanks were gradually withdrawn to rear areas as training vehicles after 1940. After 1941, not a single Wolf tank could be found anywhere near China's front lines.

After the Sino-American Pacific War erupted and Japan entered on China's side, the Wolf's obsolete tooling and production lines were sold to Japan. As aid materials, the "outdated" Wolf tanks and their variants were sold cheaply to Japan. The ultimate fate of these tanks and their derivatives: apart from the rare few on display in Chinese and Japanese museums or armored schools, most were deployed as mobile fortifications on tiny Pacific islands to confront American forces. The majority were destroyed in battle. The few survivors were never recovered. To this day, these rusting tanks remain as landscape features on Pacific islands.

Compared to the Wolf's "tragic" life, the Fox fared slightly better — its production barely exceeded a thousand. But in the end, like the Wolf, it could only cross the sea to Japan and spend its miserable latter years in that small island nation. The primary cause of these two tanks' tragic destinies was twofold: first, China's medium tank entered service too early, and the military focused armored development squarely on the medium tank category.

"The Navy is the legitimate son, the Air Force the bastard child, the Army the adopted son."

This joke, circulated among the three services at the time, was somewhat biased but clearly reflected the reality of military spending tilting toward the Navy and Air Force. During the first six years of the 1930s, the Army's budget was forced to yield precedence to the Navy and Air Force, ranking third.

"Master your fundamentals before forging equipment." "Prioritize economic development; industrialization first." "Small quick steps — more research, less deployment." As a man from the future, Chen Ke had directly stamped these two tanks with the label "obsolete by the time the world war comes in a few years." "Building too many is pure waste." Their tragic production numbers were determined from the very start.

Yet looking at the entire history of China's tank and armored forces during WWII, medium tanks served as the core, producing the Panda and Cloud Leopard — two generational classics. Heavy tanks also had the 105mm-armed "Elephant" standing proud. But light tanks? They were always a "tea table" — covered with "tragedies." "Unloved by father, unwanted by mother" doesn't sufficiently describe their wretched fate. "Baggage" might be more fitting.

Beyond the medium tank's premature success, another factor related to understanding and employing armored force structure. And there was yet another element that cannot be ignored: the "infantry tank" — a member of the tank family that historically didn't formally appear until after WWII — made its premature debut before the war thanks to the transmigrator Chen Ke, replacing the light tank's battlefield role.

Light tank development in China was at one point suspended entirely. It was not until the second year after the Sino-American Pacific War erupted that front-line troops' demands restarted the light tank development program, which had been stalled for nearly three years. But that is a story for later.