Independent filmmaker Tsukamoto Shinya was born 15 years after the end of World War II. “Neither my parents nor my grandparents ever spoke about the war, so I grew up believing, without question, that the world was a bright and peaceful place,” says Tsukamoto. “But beneath the surface, a host of people were suffering from the dark effects of the war.”

Those effects have weighed heavily on Tsukamoto’s mind over the past decade. Beginning with “Fires on the Plain” in 2014, the filmmaker shifted his focus from inventive genre films to interrogations of the whos and whys of real-world violence. “I remain deeply concerned about the state of the world today,” says Tsukamoto. “More specifically, I worry that Japan may overreact to what is happening in the world, and that we may move closer toward war as a result. That concern never left me since I made ‘Fires.’”

Premiering in Venice’s competition, “Mr. Nelson, Did You Kill People?” is the culmination of this decade of work. The film tells the real-life story of U.S. Vietnam veteran Allen Nelson, who must confront how the war upended his life as he works with a counsellor.

In a related development, nelson is a well-known figure to Japanese audiences, but a relative unknown internationally. “In Japan, he gave more than 1,200 talks about his experiences of war,” says Tsukamoto.

Tsukamoto first read Nelson’s autobiography, which the film adapts and takes its title from during his research for “Fires.” “[Nelson] wrote with extraordinary honesty about his experiences — describing not only the suffering he experienced, but also the violence he inflicted,” says Tsukamoto. “What struck me was how essential it is to understand the horror of war not only from the perspective of heroism or from the perspective of victims but also from the perspective of those who perpetrate violence.”Rodney Hicks plays Nelson. “His acting was incredibly precise,” says Tsukamoto. “Throughout the shoot, his concentration never wavered. The powerful physicality that Rodney had cultivated through years of stage work was like a sensitive antenna, reaching out to call Allen’s spirit down from heaven.” We remain with Nelson throughout — Tsukamoto notes that the film contains zero objective camera angles.

For the film to move forward, Tsukamoto says, producer Kinoshita Group “gave us one clear condition: We had to cast an actor known by audiences around the world.” The film found its recognizable face in Geoffrey Rush, who portrays the counsellor.

Furthermore, “Mr. Nelson” is the highest-budget feature that Tsukamoto has ever made, but it was achieved through his usual methods. “I operated the camera myself, handheld,” explains Tsukamoto. “We had a core Japanese crew, and worked closely with the best we could find internationally.”

That solidarity underpins Tsukamoto’s project. “When you go to war, killing people — the very thing that is considered most wrong in our everyday lives — becomes your job,” says Tsukamoto. “On the battlefield, everyone is likely to do that job, and, tragically, we find we are capable of it. I believe, if there had been no war, Allen would have been a deeply decent person. The question I want to ask is this: Do we really want to choose a path that sends our young people to the battlefield and turns them into killers?”