Alex Yeung Photo: Courtesy of Emperor Motion Pictures

China's spy thriller Cliff Walkers, the latest work by director Zhang Yimou, has dominated at the Chinese mainland box office since its release on April 30 mainly due to its fluid storytelling and down-to-earth acting.

"We knew it would make it," Alex Yeung, one of the film's executive producers, told the Global Times on Monday.

"No other film in the past 10 years had touched the genre until we did. What's more, we were deeply attracted to the script."

Zhang also showed a great interest in the story, which was in a genre that he had "never touched before."

Set in the 1930s Harbin during Japan's occupation of Northeast China, it follows a team of special agents from the Communist Party of China who are determined to complete a secret mission.

Besides its financial success, the film also has earned a 7.7/10 on Chinese media review site Douban from both movie and audience reviews, especially from moviegoers under 30.

"It can be seen as a breakthrough for China's new patriotic films," said Yeung, also vice chairman of Emperor Motion Pictures.

"Through the efforts of director Zhang, the veteran actors and others, the entire crew wanted to pay tribute to those unknown heroes depicted in the movie."

"Each actor believes in staying loyal to reality and paying great attention to every detail, including the car chase and prison torture scenes," he added.

For Hong Kong-based Emperor Motion Pictures, Cliff Walkers has been a successful attempt at a mainstream patriotic topic. "As long as we find the right scripts, we still want to film more historical and social topics, to allow young audiences to better cherish their hard-earned happy lives and arouse their patriotism," he said.