In the system of TONALITY that prevails in traditional European-rooted music, pitches are organized in a heirarchy of greater or lesser stability. The pitch having the greatest sense of stability is the tonal center, or KEY center. There are two common configurations of any given key, MAJOR and MINOR. Each of these utilize 7 primary tones with the possibility of "chromatic" decoration. Both major and minor patterns can be transposed (pitch-shifted) to any of the 12 pitches of the standard tuning system, maintaining the same half step/whole-step relationships from one pitch to the next beginning from the KEY tone (TONIC). Each of the 12 major and 12 minor keys require appropriate sharps or flats to maintain the integrity of this patterning. Thus, for example, the model MAJOR BASIC NOTE key, C Major, has no sharps or flats, while G Major has 1 sharp (F#). The basic note minor scale, A Minor has the same KEY SIGNATURE as C Major (no sharps or flats), while G Major's related minor, E Minor, has 1 sharp (F#). The concept of a key center is the primary organizing principle of traditional "Western" music.