Japan declares war on the USSR following Barbarossa

What source are you quoting from? I had never seen this much detail on planned use of biological warfare or policies for occupation of the USSR. It's an interesting contrast with Nomonhan-Khalkhin-Gol, where the Japanese were not abusive of Soviet PoWs as we would expect from this era. That could have been a sign of a more enlightened occupation policy than described in your quotes...or not. Maybe it's just a matter of scale. PoW treatment in a situation you do not want escalate to total war could easily be different than a situation where you want total war.

The source is Anatoliy Koshkin, "Kantokuen: Barbarossa in Japanese" (Russian). Those specific excerpts are pulled from the wikipedia article and rely mostly on pages 21 and 22 of the above text.

Additionally, the treatment of Soviet POWs at Khalkhin Gol was uneven; there were many cases where Russians who fell into Japanese hands were tortured and killed on the spot. The lack of massive atrocities probably had more to do with the brief nature of the fighting and the desire not to provoke Moscow, furthermore they proved useful in later negotiations where they were swapped for Japanese prisoners.
 
I think the japanese would make some advances then get pummeled a few months into the war. The soviets liberate china but the diverted rescource and lack of LL causes the germans to make more gains after their initial invasion.

You might likely see a large scale pillaging of china by the soviets as they loot industry and materials for use in their war with the germans. A 3 way war could develop with japanese fighting the soviets and the chinese fighting both of them.

WW2 ends a year or so later with the british & americans at berlin.

not really any usefull industry in China to take, unless it all the way to Chonqing. If they can go that far into China then they are fighting China itself. What they can get is raw materials and food, from China. The industry they can use is in Manchuria and Korea.

If the Soviet manage to take Manchuria and apporach Beijing the Japanese are going to go on a mass retreat to defend Korea. Mostly since they would be threathening the large ports of the north they need to supply their armies. The Japanese can hardly retreat inland.
 
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