http://www.topsecretwriters.com/2012/01/unit-731-a-u-s-cover-up-of-cruelty/
If anything, the article grossly understates what an inhuman monster that ishi and his masters were. Unit 731 may be the single most atrocity-laden group of criminals in a war that was chock full of them. Even a brief brush with their history will demonstrate why no Chinese government will ever cozy up to Japan.
Of course, after the war, we were scared shitless of the Soviets, and not without abundant reason. And when you're in such a state, you do anything that you
imagine might help. We did so in Europe, where we allowed a whole bunch of nazis to escape the noose because they claimed to have vast intelligence networks at their beck and call in the USSR and Eastern Europe. This was a complete lie, (lying nazis - imagine that!), and I can find NO evidence that any old SS goon helped this country in ANY way in discerning Soviet secrets.
Well, our boy ishi is in the same class. The article states that he was a "talented medical researcher", but I've read histories that his so-called research was garbage - anecdotal reports without any serious effort to quantify what was done, etc. Basically, a middle schooler trying to imitate a real scientist. Yes, his unit did have some moderate success in infecting regions of China at various times, but their methodology was sloppy and impossible to judge/reproduce. The guy was great at killing people, especially his 'lab-rat' victims, but not at providing documentation for how to advance. In other words - one more worthless monster whom we hired on while in a panic.
Just one more example of how morality becomes very grey indeed when dealing with geopolitics.