The cause of aggression and conflicts leading to the Nanjing Massacre in China and contributing to the start of World War II can be identified in the following timeline:
1. **1910s-1920s**: Japan's expansionist policies in Asia, such as the annexation of Korea in 1910 and involvement in the Siberian Intervention during the Russian Civil War, signaled its imperial ambitions.
2. **1931**: The Mukden Incident in Manchuria, where Japan falsely claimed Chinese sabotage as a pretext to invade and establish the puppet state of Manchukuo, marked a significant escalation of aggression.
3. **1937**: The Marco Polo Bridge Incident near Beijing led to full-scale war between China and Japan. The subsequent brutal occupation of Nanjing by Japanese forces resulted in the infamous Nanjing Massacre, with hundreds of thousands of Chinese civilians and prisoners of war brutally killed.
4. **1939**: The invasion of Poland by Germany, allied with Japan through the Anti-Comintern Pact, triggered the start of World War II in Europe.
These events illustrate the escalating aggression and conflicts that culminated in the Nanjing Massacre and contributed to the outbreak of World War II, highlighting the complex geopolitical dynamics of the time.
