A method for controlling a washing machine is described. The method includes washing laundry by rotating the pulsator in alternating directions with at least a portion of the laundry soaked in wash water in the washing tub. The method further includes draining the wash water from the washing tub; supplying additional wash water into the washing tub. The method further includes increasing a rotation speed of the washing tub with the laundry soaked in the additional wash water. The method further includes sensing a degree of vibration while increasing the rotation speed of the washing tub. The method further includes, based on the sensed degree of vibration being smaller than an allowable degree of vibration, dehydrating the laundry by draining the additional wash water from the washing tub and rotating the washing tub at an increased rotation speed.