During World War II, the Imperial Japanese Army's Unit 731 in occupied Manchuria, China, conducted biological warfare experiments releasing plague-infected fleas via bombs over Chinese cities like Ningbo and Changde. This caused outbreaks killing thousands. It occurred primarily in northeastern China. It mattered as a grim example of animals as weapons, violating international norms and accelerating post-war bioethics debates.

This event influenced post-war literature and poetry on atrocity and human cruelty, echoing in works addressing biological horror similar to plague motifs in European canon. It shaped anti-war verse and narratives by Asian poets exploring trauma and imperialism. (124 characters)