OK. Japan would only be taking Vladivostok. Thats it. They didn’t have any other capabilities to do anything more and the return on investment is negative due to the deplorable nature of the terrain.
Just imagine a space the size of 15 Mongolia with dense forests, unimproved roads, no electrical, nothing and subtract 30 degrees. The only thing is to march along the railroad line and get cut off easily by flanking attacks from the wilderness. Great fun.
And those so called Japanese tank corps? You might just call them “tin coffin death traps” easily sabotaged with land mines and other obstacles. Japan had no means to control any logistical train longer than about 200 miles, just look how they did in China from 1931-1945… they didn’t get farther than a few hundred miles in the interior and this is substantially improved road system.
It it beyond any imagination to consider anything from Japan more than what they did in 1904-5 during that war against Russia.
Russia already proved who were better trained and better equipped in fighting during 1939, and thats after the great purges so technically Japan was no match for the Soviets.