The documentary also incorporates Japanese historical materials, including participants' oral accounts, combat reports and war criminals' confessions, all presented with Japanese voice actors reading the accounts. "This approach wasn't meant for argumentation, but to let the facts speak for themselves."

A poster for "Mountains and Rivers Bearing Witness." [Photo courtesy of Huaxia Film]

Han said that a core theme of the film is the pivotal role of the Communist Party of China (CPC). "We engaged in continuous discussions with experts, held countless planning meetings within our team, built frameworks, dismantled them and rebuilt them, until we finally identified a clear narrative thread: Examining the pivotal role the Communist Party of China (CPC) played in every major historical event throughout the 14-year War of Resistance," Han said.

Despite its focus on war's brutality, Han said the documentary's ultimate message advocates for peace.

"Powerful nations bear greater responsibility in safeguarding peace … Through this documentary, we hope to help contemporary audiences understand that war must be avoided whenever possible, to prevent ordinary people from suffering its devastating consequences."