Premise: The Nanking Massacre was an episode of mass murder and mass rape committed by Japanese troops against the residents of Nanjing ("Nanking"), then the capital of the Republic of China, during the Second Sino-Japanese War. The massacre is also known as the Rape of Nanking or, using Pinyin romanization, the Nanjing Massacre or Rape of Nanjing.
Hypothesis: The first world war lead to the Nanking Massacre