In the war crimes tribunals that followed Japan's defeat in World War II, the issue of waterboarding was sometimes raised. In 1947, the U.S. charged a Japanese officer, Yukio Asano, with war crimes for waterboarding a U.S. civilian. Asano was sentenced to 15 years of hard labor.
"All of these trials elicited compelling descriptions of water torture from its victims, and resulted in severe punishment for its perpetrators," writes Evan Wallach in the Columbia Journal of Transnational Law.
On Jan. 21, 1968, The Washington Post ran a front-page photo of a U.S. soldier supervising the waterboarding of a captured North Vietnamese soldier. The caption said the technique induced "a flooding sense of suffocation and drowning, meant to make him talk." The picture led to an Army investigation and, two months later, the court martial of the soldier.
Waterboarding: A Tortured History : NPR