In music, a hundred twenty-eighth note or semihemidemisemiquaver or quasihemidemisemiquaver is a note played for 1⁄128 of the duration of a whole note. It lasts half as long as a sixty-fourth note. It has a total of five flags or beams.
A single 128th note is always stemmed with flags, while two or more are usually beamed in groups. Notes this short are very rare in printed music, but not unknown. One reason that notes with many beams are rare is that, for instance, a thirty-second note at
These five-beamed notes also appear occasionally where a passage is to be performed rapidly, but where the actual tempo is at the discretion of the performer rather than being a strict division of the beat. In such cases, the aggregate time of the notes may not add up exactly to a full measure, and the phrase may be marked with an odd time division to indicate this. Sometimes such notation is made using smaller notes, sized like grace notes. One rare instance where such five-beamed notes occur as acciaccaturas occurs in the final measures of No. 2 of Charles-Valentin Alkan's Trois grandes études, Op. 76.
Hundred twenty-eighth rests are also rare, but again not unknown. One is used in Beethoven's Piano Sonata No. 13 "Quasi una fantasia" (bar 24 in the adagio movement) where it is followed by an ascending run of 128th notes.
The listener is right to suspect a Baroque reference when a double-dotted rhythmic gesture and semihemidemisemiquaver triplets appear to ornament the theme.)[full citation needed]