An Introduction about Drop Stance by Ilchi Lee: Extending one leg stimulates the Gall Bladder Meridian, filling a person with confidence, and trains the hip joint; bending the other leg trains the thigh. Bu-toe-bo is a stance in which the distribution of strength in the legs must be maintained since they take very different shapes. It is effective for causing energy to sink in a stable way.
Set: Bu-toe-bo is adapted from Ki-ma-bo by bending one knee and sitting down on one leg while straightening the other leg. Make sure that the knee of the supporting leg does not come out of alignment with the toes of the foot below it. Your feet should be parallel, with the toes pointing the same direction. When the left leg is extended, the stance is called Jwa-bu-toe-bo; when the right leg is extended, it is called U-bu-toe-bo.