As you prepare to practice Ball to the Valley, imagine an energetic vessel in the shape of a large cylinder standing upright directly in front of you. The top is open to the heavens above and the bottom has tubular roots extending deep into the earth. Imagine that this vessel is the primary corridor for the flow of chi (life energy) through your body. 

When practicing Ball to the Valley, imagine that as you rock forward and lower your arms, your open hands are collecting a ball of earth energy. This is the calming energy that can be felt when walking barefoot on the grass, hiking in a forest, or trekking through the desert. Even though the roots of the vessel extend down into the earth, imagine that your ball of earth energy slides right into your imaginary energetic vessel near the height of your bent knee. This is the "the valley". 

As you rock back, raise the ball of earth energy up through the vessel. As the ball rises throught the vessel, it fills any energetic gaps with calming earth energy. If no gaps are found, the energetic vessel expands to make room for the earth energy.  In this way your energetic vessel, becomes a grounded source of calm and connectedness.