3. INDEPENDENCE OF LINE. The integrity of each line must be preserved. That means that the releases and legato in one line must not be influenced by the activity of another.
The green highlights to the right indicate places where one part plays legato (think heavy) at the same moment that the other part breaks (think light). For beginning organists, this is the most frequent and stubborn type of challenge with independence.
The yellow highlight is an example of one part moving in a different direction than the other.
If you discover a problem in keeping the left hand and the pedal parts independent, the freezing technique is a particularly effective approach.