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, many 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.

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.