A dark chapter from World War Two has left people in China with a toxic legacy. Large quantities of chemical weapons abandoned by Imperial Japanese forces at the war's end continue to cause suffering. The weapons were manufactured secretly, and used illegally. After Japan's surrender, troops discarded the bombs around China, dumping them in rivers or burying them.

On September 2, 1945, Japan surrendered to the allied forces at a ceremony in Tokyo Bay, officially closing World War 2. Officials from the United States, United Kingdom, Soviet Union, and China observed the signing of the instrument of surrender aboard the USS Missouri.