The following text describes how the forearm is used in tone production. The forearm has its fulcrum at the elbow and moves in three basic ways.

1. The first is a vertical movement and swings the forearm up and down from the elbow. It is a very tiring movement if instigated by the muscles of the arm, but if the movement is initiated by the pluck of the fingertips, the arm moves as a free body in a passive state and there is no tension generated.
2. The second movement is a lateral movement and is useful in getting the fingers across the piano. This lateral movement also becomes an element of the walking arm and is indispensable to keyboard technique. This lateral movement is somewhat cumbersome, but can be done slowly once the motion has been mastered during practice.
3. The third movement, and the most important is the rotary motion of the forearm, better known as rotation. This movement involves
   1. the rotation of the forearm to supination, which is the palm of the hand upward and visible, and
   2. to pronation, rotation of the forearm so that the palm of the hand is downward.
   It is rotation of the forearm, when coordinated with the action of the fingertips, that compensates for the natural inequity of the fingers and results in tonal equality and power.

The upperarm has its fulcrum at the shoulder and has three basic movements.
See Figure 6 at Geometry of Movement

1. The first a vertical movement, is very cumbersome and is best avoided at all times.
2. The second a lateral movement is usually confined to large leaps, when the arm is sent through the air as a free and passive body, steadied by the influence of the upperarm.
3. The 3rd and most important movement is the in-and-out movement, for the upperarm is the ony limb able to perform this movement of the whole arm, hand and fingers.
   1. "In" refers to movement into the black key area of the piano, and
   2. "out" refers to movement away from the piano and towards the player.
   The right combination of the foregoing movements lead to a skilled and free technique.