In early January of 2017, the People’s Republic of China’s Ministry of Education made an unprecedented announcement: the starting date for China’s World War II, known domestically as the War of Resistance against Japan, would be shifted back 6 years. Instead of starting with the Marco Polo Bridge Incident on July 7, 1937, as was widely assumed previously, the war would now start with the Mukden Incident on September 18, 1931 with the Japanese Kwantung Army’s invasion of Manchuria. Although it would be easy to write off the new official policy as a strictly top-down affair, however, the reality was more complex. Starting in the 1980s, a number of regional historians, particularly from China’s Northeast, clamored for a 14-year timeline to encompass the invasion of their homeland. In my research, I examine this regional scholarship alongside rebuttals in favor of the 8-year war timeline that resulted in a robust “date debate” from the 1990s through 2015. In addition, I argue that the Chinese Communist Party had several powerful incentives to rewrite the war’s timeline: domestically, this strengthened the Party’s overall legitimizing narrative, while internationally, it enhanced the Party’s reputation as a responsible geopolitical player on the global stage.