Japanese Unit 731

[stefanob]

Hello everyone,
I know this is a little off topic, but not that much.
I was wondering if anyone has informations about the Unit731, described as:

...a covert biological and chemical warfare research and development unit of the Imperial Japanese Army that undertook lethal human experimentation during the Second Sino-Japanese War (1937–1945) and World War II.

http://en.wikipedia.org/wiki/Unit_731

Did this actually exist? Or is it like the Nazi gas chambers?

Thank you in advance