The Diruta in the book "Il Transilvano" deals with musical art scrupulously giving us important rules on the way to play, from the approach to the instrument, to the position of the hands and the body, the fingering and the way of interpreting embellishments. Transylvanian is of great importance for all the organists who intend to deal with Renaissance music.
One of the fundamental rules expressed by fingering is the concept of a good finger and a bad finger. The good fingers must be used to play the good notes, that is the accented ones, while the bad ones must be used for bad notes, that is the unaccented ones. Depending on the situation, then the fingering must be chosen so that the good fingers are on the good notes. The good fingers are the second and fourth (index and ring) and bad first, third and fifth fingers (thumb, middle and little finger). Therefore in the known good-bad passage the fingering 2,3,4,3,4 will be followed, etc. in an ascending sense; descending note good bad 4,3,2,3,2,3 etc. The Diruta continues the degree is when the notes continue one close to the other, ascending and descending. The good leap, when the notes jump, is of the octave or of the sixth, or of other consonant intervals, and dissonant; for that the good note is the one that jumps and this is called good jump. the bad jump is when the bad note skips. The good jump touch is in the second tone (to understand only the minor). I hope I was clear in the illustration of the subject.