BEIJING, July 4 (Xinhua) -- A U.S. documentary chronicling Japan's notorious 1937 invasion of the Chinese city Nanjing will open in Chinese cinemas on July 7, the 70th anniversary of the Warof Resistance against Japan.

    The 90-minute documentary, "Nanking" (the old spelling of the city's name), features interviews with Chinese survivors and Japanese soldiers, along with pictures, letters and diaries read by actors portraying Westerners who helped save more than 200,000 Chinese refugees in Nanjing.

    The documentary also includes film footage shot by John Magee, an Episcopal pastor in Nanjing from 1912 to 1940, who recorded them assacre and rescued many Chinese people.

    On July 7, 1937, the intruding Japanese forces assaulted Lugou Bridge and Chinese soldiers responded by gun fire. This has been known as the Lugou Bridge Incident, or "July 7 Incident", which marked the beginning of the War of Resistance against Japan in China.

    The Nanjing Massacre occurred in December 1937 when the Japanese troops occupied the then capital of China. More than 300,000 Chinese are believed to have been murdered and thousands raped.

    Ted Leonsis, the film's producer, said the decision to put the Nanjing Massacre on screen was made after he read the Rape of Nanking, written by Chinese American author Iris Chang in early 2005.

    Leonsis, also AOL vice chairman, said he was ashamed of his ignorance of the atrocity and realized that most Americans had no idea what had happened in China in the winter of 1937.

    In the summer of 2005, Leonsis invited the Academy Award-winning writer/director team of Bill Guttentag and Dan Sturman to shoot the documentary.

    To find the materials that would bring the story of Nanking to life, Guttentag, Sturman and their production team collected thousands of pages of letters, journals and diaries for three months by trawling original sources and archives in the United States, Europe and Asia.

    In China, they met historians, archivists, and scholars who told them where to look for the best photographs and footage in China and across the world.

    The team also interviewed 22 survivors in the cities of Nanjing, Suzhou and Shanghai.

    Filming in Japan was more difficult. The production team said it was challenging to find former Japanese soldiers willing to talk about their experiences in Nanjing. The Japanese soldiers who participated in the film were found through members of the Japanese peace movement.

    Upon returning from Asia, the Nanking production team began the final piece of the filming -- the staged reading with actors. Filming took place in Los Angeles in August 2006.

    The documentary was narrated by Woody Harrelson, Stephen Dorff and Mariel Hemingway.

    In January 2007, the documentary Nanking debuted at Sundance Film Festival where it received the Editing Award. In April, it won the Humanitarian Award for Best Documentary at Hong Kong International Film Festival.

    The documentary was premiered in Beijing on Tuesday. In North America, it will be released by THINKFilm in December to coincide with the 70th anniversary of the massacres in Nanking.