A movie was made about this, its called Men Behind the Sun . The movie is absolutely horrific. Apparently the director was banned from making movies after its release for doing awful things to animals and cadavers. Worth a watch.

Its kind of sad how they managed to whitewash that from history

Everybody did a lot of bad shit in WW2. Nobody is the worse bad guy when it comes to how we treated our fellow humans. Some of the things that happened could be categorized as more brutal or whatever, but you've already crossed a line at that point, where the distinctions regarding how exactly you torture and kill somebody don't really matter. We all crossed the line.

Whats the conspiracy part of this TIL though, im trying to figure out.

Yes in terms of war crimes the Japanese Empire excelled at a high level. The primary distinction that sets the Nazi's apart isn't the volume of their crimes but rather the methodical, industrialized process by which they sought to extinguish entire groups of people. The Japanese never saw the Chinese as raw parts to be dealt with accordingly, they saw them as humans who should be murdered and subjugated however they wished. Sadly the latter option is far more normal human behavior.