Nanking Massacre Memorial Day is observed in China every December 13 to honor the victims of the Nanking Massacre, a tragic event during the Second Sino-Japanese War. This day commemorates those who were killed when the Imperial Japanese Army captured Nanjing, the then-capital of the Republic of China, on December 13, 1937. Over the following six weeks, Japanese soldiers committed numerous atrocities, including the murder of civilians and disarmed combatants, alongside widespread theft, looting, arson, and rape. The estimated death toll ranges from 40,000 to 300,000, although the exact number remains unknown due to the destruction of records after Japan's surrender in World War II. Nanking Massacre Memorial Day was officially added to China's holiday calendar in 2014 and has been observed annually since then.