due to political censorship by the government.
The literal translation of the title of this movie is: The Great Flight of 731.
Although the movie is based on the actual event that really happened, as in most of the Chinese war movies, it did not tell the complete story.
The thing that the movie willfully ignored was the atrocities Soviet troop committed against Chinese civilians, such as looting, raping and murdering. The official Soviet explanation was that due to massive Japanese immigration to China, there were a large number of Japanese residing in Northeastern China and Soviet troopers could not distinguish between the Chinese and Japanese so that in retaliation of Japanese, many Chinese became victims.
In reality, however, this was due to the poor discipline of Soviet troops because when the original Soviet far eastern troops were deployed to Europe to fight Germans and consequently, as the occupation force in Eastern Europe, the newly formed replacement Soviet far eastern troops used to fight Japanese were ex-convicts released from labor camps, in exchange of amnesty, they serve in Red Army to fight Japanese. Obviously, one could not be surprised by the crimes these ex-convict troops. This is something the Chinese government would not want to advertise, and the film dared not to touch due to certain political censorship if it ever did.