Musical notation its "natural" form, which means that any sharps or flats applying to that note from the key signature or from accidentals are cancelled. Sometimes a courtesy accidental is used in music where it is not technically required, to remind the musician of what pitch the key signature requires. Following the key signature is the time signature. The time signature typically consists of two numbers, with one of the most common being "4/4". The top "4" indicates that there are four beats per measure (also called bar). The bottom "4" indicates that each of those beats are quarter notes. Measures divide
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