Key signature key signatures showing sharps or flats on both octaves for notes which fall within the staff. An accidental is an exception to the key signature, applying only to the measure and octave in which it appears. Although a key signature may be written using any combination of sharp and flat symbols, the most common series of thirteen homogeneous key signatures—ranging from six flats to six sharps, with each successive flat or sharp placed on the note a perfect fifth below or above, respectively, the previous one—is assumed in much of this article. A piece scored using a single diatonic key
Music of southern China Perfect-fourth transposition of the melody ("fan") also occurs, though the tonal centre remains constant. Four or five main modes ("diao") are traditionally identified. However, while elsewhere in China such modes are mainly defined by absolute pitch and by the degree of the pentatonic scale that is taken as the key-note (thus setting the intervals of the scale), the xianshi conception of mode, rather like the Indian raga system, includes motif, ornament and intonation. Pitch is not absolute but the scale is usually constructed on a key-note approximating to western concert F – F#. Modes are pentatonic but all derive from