Another description of Japanese "water torture":A type of funnel, usually formed from a towel, was placed over the victim's mouth and nose. At the same time, a 5-gallon can was filled with water and usually urine and kerosine. The concoction was poured into the funnel, and the victim had to either swallow all 5 gallons of this mixture or drown.
Having swallowed 5 gallons of this liquid, the victim's stomach would stretch and swell. The victim would then be bound, often with barbed wire, and the stomach would be struck, either with a rod of some sort or soldiers would even jump on it, depending on how the prisoner was bound. This pressure could easily cause the bloated stomach to burst. If not, the victim was then hanged by his ankles and the liquid would drain out through his mouth, risking drowning once again. The process could then be repeated.