Braces, Brackets, Systems: A Musician's Guide

Braces, brackets and systems are among the most basic notational elements in music. They play a fundamental role in imposing order and clarity on a score. Yet many students and even some experienced musicians are fuzzy in their ability to define the three terms involved and to differentiate the complete range of uses for each of the three symbols.

Brace
The brace, sometimes called a curved bracket, is shaped somewhat like an archer's bow: {.

It functions most often to connect the staves (at their left margin) of a single instrument whose music is conventionally written on two staves, such as the piano, organ, celesta, harpsichord, and harp.

If, as sometimes happens in piano music, three staves are used, then all three staves are enclosed in the brace. However, if organ music has a third staff for the pedal part, only the two staves for the manuals are braced (the pedal part being, in effect, for a different "player"-the feet).

Some composers and publishers use small braces between the staves of music for a two-staff instrument or between two adjacent staves for related instruments in an ensemble score. The brace here indicates that dynamics or other directions apply to both staves. This notational technique saves time and space, especially in full scores for large bands or orchestras.

Brackets
The music bracket looks similar to the common symbol known as a square bracket: [. However, the music bracket differs by having thin curved ends that extend above and below the outer staves.

Unlike the brace, which connects the multiple staves of a single instrument, the bracket connects the single staves (at their left margin) of multiple instruments.

For example, a duet for flute and bassoon would have the two staves connected by a bracket. A bracket would also be used to link the three staves of a piece for three clarinets (playing three different parts) and the four staves of a string quartet. In a full score for a large ensemble, such as a band or orchestra, a bracket usually sets off each of the four main instrumental sections: woodwinds, brasses, percussion, and strings.

Systems
A system is a group of staves designed to be read (and played) together instead of one at a time. It consists of two elements. The first element is a single vertical line through the left edge of all the staves in the group. The second element is one or more braces or brackets at the left of the vertical line.

Most of the braced or bracketed groupings mentioned above are systems that simply need the addition of the vertical line for clarity.

For example, a keyboard or harp system consists simply of a vertical line through the two staves in addition to the brace at the left of the line. A typical organ system consists of a line through all three staves (two for the manuals and one for the pedal) in addition to the brace at the left of the two staves for the manuals.

One of the most common systems is for a soloist (such as a singer or violinist) with piano accompaniment. The first (top) staff is for the soloist. Below that are the two staves for the piano. The system consists of a vertical line through all three staves plus a brace for the piano. The soloist part, like the pedal part for the organ, has no brace or bracket.

The duet for flute and bassoon, the clarinet trio, the string quartet, and similar bracketed small ensembles can each be turned into a system by adding a vertical line through the affected staves.

Even a large system, for a band or orchestra, is primarily characterized by the single vertical line through the staves of all the parts. As mentioned above, each of the four main instrumental sections is usually set off by its own bracket.

However, composers and publishers vary in their use of secondary braces or brackets in large ensemble scores to connect the staves of smaller groupings of instrumental families. For example, if the horns in F are on two staves, some notators will, and others will not, brace or bracket those two staves.

Avant-garde composers have invented unorthodox techniques for using braces, brackets, and systems. However, the above guide is the traditional, and still mostly widely followed, use of the three symbols.