During WWII, Japan secretly established the notorious Unit 731 in Harbin, northeast China, which served as the command center for its biological warfare program. At least 3,000 people were subjected to human experimentation by Unit 731, while hundreds of thousands of people in China were killed or injured by Japanese biological weapons. Despite this history, some Japanese political forces have long sought to deny the country's wartime atrocities, even attempting to portray Unit 731 as a "public health research unit." However, mounting evidence continues to expose the truth about its horrific crimes.