June 1956- - Rommel and the other panzer divisions are now pushing across the Tibetan Plateau. Clearing away Japanese outposts, with massive bombardment, the tanks roll into Quighai and the Sichuan Basin. The ancient city of Chengdu falls on June 17th. In the north, Harbin and Baotou fall on June 20th, as Japanese troops fall back to the old capital of Peking (also known as Peiping or Beijing), already being attacked from the air by Junkers-107 or "King Stuka" dive bombers.
In the air, the Japanese Air Force and Naval Air Forces were almost totally decimated by the 12th of June. Six German carrier groups, including the two new nuclear-powered aircraft carriers "Barbarosa" and "Thorsten", entered in the Pacific and were striking both Japanese naval vessels and ground bases, but Japanese civilian cargo ships as well. The U-boat flotillas were already hard at work on the civilian freighters, sinking nearly 500,000 tons in the few two weeks alone. As with OTL, the Japanese Home Islands were vulnerable to the sinking of its cargo vessels, which brought vital resources to the factories of Japan.
Per Heydrich's orders, no further nuclear bombardment was made. German nuclear weapons were still in short supply, with only five remaining "Wasserstof" or hydrogen bombs, and a dozen of the older fission weapons. But conventional bombing and incendiary bombing continued, primarily focused on Japanese airfields, naval bases, and some key armament factories. 935,000 people died in the aerial attacks of June, in addition to the hundreds of thousands already dead from the nuclear bombardment.
On June 29th, the German panzers finally reached Peking and Chungking (or Chongqing). Japanese forces were told to hold both cities at all costs, and tried. 510,000 soldiers were deployed in the two cities, with every available aircraft available launched from Korea, Hong Kong, and Taiwan to assist. The Germans believed that the Japanese were trying to "hold a line" and slow the advance until guerrilla action could be co-ordinated in western and northern China. In fact, it was a mere delaying tactic until the Japanese employed its "final option."
Unit 731, or officially the Kempeitai Political Department and Epidemic Prevention Research Laboratory, had been known, if vaguely, to the Germans since the late 1940s. It was known that the Japanese employed several different forms of human experimentation, primarily on the Chinese, to develop and weaponize various infectious diseases for biological warfare. The facilities that were known about, in Singapore and Harbin, had been bombed with incendiary weapons at the outset of the war (as a precaution to prevent viral agents from being dispersed). But others remained or were deep underground (in secret labs built in the mid-1940s to escape German detection and possible destruction).
Though German agents were well aware of the human experimentation done in their own concentration camps, many found those done by the Japanese even more horrifying. However, they were quite effective. By 1951, the Japanese had weaponized both anthrax and bubonic plague. By 1955, mass production of those agents had been accomplished and stationed at secret bases all through Asia. Prime Minister Tanaka's successor, General Shozo Sakurai, seeing the inevitability of German domination of China, Korea, and Southeast Asia, ordered that upon the sieges of Peking and Chungking...biological agents were to be deployed against the German forces.
On July 2nd, fighting began in the two cities. Japanese forces employed similar methods used in OTL's Battle of Stalingrad, using the ruins of the city as cover and keeping their front lines as close together as possible. Eventually, the German tanks were useless in the streets covered with debris and the Wehrmacht infantry was forced into the open. When this occurred, the Japanese employed their "human wave" attacks, sending groups of 500-700 men against German positions, losing up to 80-90% of them, but the survivors wreaking havoc on the terrified Germans, forcing them to pull back and re-organize.
Divine Wind - Finally, the predominance of German air cover was too much and General Tomitaro Horii, commander of the Northern division guarding Peking, radioed Kobe (new Imperial capital) that the city was lost. Nearly two hours earlier, the commander in Chungking, relayed a similar message. Prime Minister Sakurai ordered "Section J" into operation.
50 of the remaining Nakajima G9L jet bombers were launched from Nagasaki, 25 to Peking, 25 to Chungking. They each had 50 porcelain bombs, carrying some two and a half liters each of a bubonic plague mutant called "SJ-53". Luftwaffe radar picked them up 20 miles from the cities and interceptors were immediately launched. Five of the bombers heading for Peking and six of the ones heading for Chungking were downed. The rest were able to drop their payloads before they too were shot down.
German bio-chemical warfare was state-of-the-art. After all, they had developed both chemical and biological weapons themselves, but never deployed the biological agents before (except on test subjects in African experimentation camps). When the ground commanders in Peking saw that an aerosol substance was emerging from the bombs dropped, they ordered their troops to don their bio-chemical protection suits. Unfortunately, many of the troops had become lackadaisical (with no deployment by the Japanese so far) and the suits were not properly maintained or not properly sealed upon wearing. Regardless, the full force of the viral agent hit some 530,000 German troops in both cities.
SJ-53 was very similar to "normal" bubonic plague, except that it had been made airborne and ten times more infectious. While normal anti-bacterial agents might cure a patient, SJ-53 was highly resistant to antibiotics and spread almost twice as face to the lymph nodes. By July 4th, half the Germans infected were incapacitated. By the 6th, 90% of the infected were dead, even those able to be transferred back to rear echelon mobile medical centers. The German land offensive in Asia ground to a halt. (Note: the half million Japanese troops in those areas also died, as they were expected to. All of them had taken an oath, the Oath of the Shinpo or "divine wind", to die by whatever means to stop the Germans from taking the cities. The German translators mistaken termed this by another phrase for "divine wind" in Japanese...."kamikaze.")