halfflats

Half-flats are a type of microtonal accidental used to indicate a pitch that lies between the standard chromatic steps. In systems that extend beyond the ordinary sharp and flat, a half-flat lowers a note by less than a full flat, placing it between the natural note and its flat. The exact pitch of a half-flat depends on the tuning or notation system in use; different microtonal grammars assign different cent values or step sizes. As a result, half-flats are not standardized across traditions.

Notation for half-flats varies. In some scores, they are written as a flat symbol with a diagonal stroke or as a dedicated half-flat sign. Other writings spell the pitch as an enharmonic name appropriate to the chosen system (for example, spelling a note that lies between C and C♭ with a name indicating a half-step alteration). A legend or key in the score explains the precise value.

Half-flats appear primarily in 20th-century and contemporary music that explores microtonality, including works for traditional voices and instruments, as well as electronic and computer-based notation. Composers such as Alois Hába and Ivan Wyschnegradsky used microtonal systems that include half-flat or similar alterations. In modern practice, performers rely on the score's tuning guidance and, in electronic contexts, on software tolerances for precise pitch.

In sum, half-flats are among several microtonal accidentals used to extend pitch vocabulary beyond the standard 12-tone equal temperament, enabling finer distinctions between adjacent notes.