Open Crotch Pants, also known as open-crotch trousers or split pants.In Chinese is KaiDangKu(开裆裤). Which are worn by toddlers throughout mainland China.Often made of thick fabric, they are designed with either an unsewn seam over the buttocks and crotch or a hole over the central buttocks. Both allow children to urinate and defecate without the pants being lowered. The child simply squats, or is held by the parent, eliminating the need for diapers.