Alla breve
The half note rather than the quarter as beat; four-four time counted in two.
What it means
Alla breve denotes a metre in which the beat is not the quarter note but the half note. Four quarters per bar become two halves: the bar has the same note content as a four-four bar but is felt in two beats rather than four. The name goes back to the brevis, a note value of mensural notation, and has persisted as the designation for cut time.
Alla breve is thus first of all a statement about the counting unit, not about the speed. In practice the two hang together: a piece is usually notated alla breve precisely because it is too fast to count quarters sensibly. The metre is to be distinguished from two-four time — this too has two beats, but the quarter as beat and hence a smaller basic unit, as well as half as much note value per bar.
In the notation
The sign is a struck-through half-circle, ¢, and stands in place of the time signature at the beginning of the line; equivalently 2/2 is written. It holds until a new time signature appears. The half-circle C without a stroke, by contrast, stands for four-four time. The two signs differ only by the stroke and are easily confused in quick reading — a glance at the beaming helps: in alla breve, eighths and sixteenths are usually grouped into groups of one half note each.
Musical use
The metre is typical of quick movements with running motion: closing movements of Classical symphonies and sonatas, marches, fugues with a fast subject. In the vocal polyphony of the sixteenth century, alla-breve counting is the normal case, and the ecclesiastical style later called stile antico stays notated in large note values and half-note beats precisely for this reason. Chorale settings too frequently appear alla breve, because the melody lies in long values.
Performance practice
First change your way of counting before you raise the tempo: two beats per bar, not four. Whoever goes on thinking in quarters plays ponderously and stresses too many notes. Set the metronome to the half note — depending on the piece and edition around 60 to 88 beats per minute — and feel the quarters only as a subdivision. Watch the emphasis: in alla breve the first half is the heavy beat, the second the light one; the quarters in between carry no weight of their own.