Key Signature
The sharps or flats after the clef — which notes the piece mostly uses
Related
A key signature is the group of sharps or flats between the clef and the time signature. It says which notes the piece uses by default — two sharps usually mean D major or B minor — so the score need not repeat an accidental on every note.
A key signature is not a key: D major and B minor share the same signature, and only the centre and the cadences tell them apart. A piece can also modulate while the signature stays put (or changes), so the heard centre moves even when the notation does not. A key signature is a notational convenience, not the music's home.
Read deeper → Key Signature
Sources
- 调号的记谱规则与关系大小调的共享，参 The New Grove Dictionary of Music and Musicians, "Key signature"；本文为原创表述
Used for fact-checking only; all prose is original.