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
Key signature signature that appears at the end of a line immediately before a change is usually preceded by an additional barline; the line at the very end of the staff is omitted in this case. If both naturals and a new key signature appear at a key signature change, there are also more recently variations about where a barline will be placed (in the case where the change occurs between bars). For example, in some scores by Debussy, in this situation the barline is placed after the naturals but before the new key signature. Hitherto, it would have been more usual