Key signature A minor as each accidental may be notated explicitly as required, or the piece may be modal or atonal. An example is Bartók's Piano Sonata, which has no fixed key and is highly chromatic. If not bound by common practice conventions, microtones can also be notated in a key signature; which microtonal symbols are used depends on the system. The common practice period conventions are so firmly established that some musical notation programs have been unable to show nonstandard key signatures until recently. The use of a one-flat signature developed in the Medieval period, but signatures with more than one
Numbered musical notation 3 4 5 6 7" to raise or lower the pitch and placed after the note names "C D E F G A B", which are used for key signature and chord markings in the numbered system. But these accidentals are relative to the diatonic scale (1 2 3...) rather than the note names (C D E...). For example, even though the leading note for the harmonic C minor scale is "B natural", it is written as "5". Key signature changes are marked above the line of music. They may be accompanied by symbols that represent the note's degrees at