"Evil Unbound," a film exposing the atrocities of Japan's notorious Unit 731, held its world premiere Wednesday in Harbin – the capital of northeast China's Heilongjiang Province and the city where the infamous germ warfare unit was once based.

The film tells the story of Wang Yongzhang, a local vendor and others imprisoned in the "special prison" of Unit 731. Lured by false promises of freedom in return for cooperating in supposed health checks and disease prevention research, they instead became victims of horrific medical experiments, including frostbite tests, gas exposure, and vivisection.

"The true history is far more brutal than what the film can show," said Jin Chengmin, curator of the Exhibition Hall of Evidence of Crimes Committed by Unit 731 of the Japanese Imperial Army, at the premiere.

The crimes of Unit 731 rank among the darkest chapters in human history, and its atrocities were carefully covered up by Japanese authorities afterward, he noted, adding that it is hoped this film will bring more attention to the understanding and study of Unit 731 and its history.

Unit 731, a top-secret biological and chemical warfare research facility, was established in Harbin's Pingfang District and served as the command center for Japanese biological warfare efforts in China and Southeast Asia during World War II.

Historical records suggest that between 1940 and 1945, at least 3,000 people were used in human experiments by Unit 731, while Japan's biological weapons killed more than 300,000 people in China.

Zhao Linshan, the film's director, mentioned that the production team relied on a rich collection of authentic historical materials. He expressed hope that the film will serve as a powerful reminder to the world of this dark history and inspire people to truly value peace.

The film is set to premiere in other parts of China on Thursday, which marks the 94th anniversary of the September 18 Incident that signaled the start of the Chinese People's War of Resistance Against Japanese Aggression.

Before its official release, the film had already attracted significant attention in China. By Tuesday night, data from Chinese movie ticketing platform Maoyan showed that 4.5 million people had expressed interest in watching the film, with advance ticket sales totaling 108 million yuan (about $15.2 million), and 217,000 screenings scheduled for its opening day.

The movie will also be released globally starting Thursday, with screenings scheduled in countries and regions including Australia, New Zealand, the United States, Canada, the Republic of Korea and China's Hong Kong and Macao.

This year marks the 80th anniversary of the victory of the Chinese People's War of Resistance Against Japanese Aggression and the World Anti-Fascist War.

As the world's largest ruins of a germ warfare research site, the location that hosted Unit 731 holds significant historical and educational value. These ruins were added to China's tentative list of world cultural heritage sites in 2012.

(With input from Xinhua)