Making use of the << and >> idea to indicate simultaneity, if a note has multiple pitches indicated between > and < then LilyPond assumes that they are in a chord together. Notating a single chord with single < > brackets has two advantages: firstly, it is easier to see that they are a chord and not something more complex; secondly, it allows you to enter information more clearly.

Consider the following examples, which should produce equivalent output: <<g'4->-5 b d>> and <g' b d>4->-5 With the first example, it is more difficult to see the chord notes, the duration, and what the 5 means. With the second example, it is easy to see that the chord notes are a G, a B, and a D, that they have quarter-note duration, and that the 5 is actually a fingering indication.

There is another advantage to using < and > for notation of simple chords: they preserve logical continuity in "relative" mode. The following note will always be notated as relative to the lowest note in the chord, regardless of how many octaves the chord covers. This is not true with << and >>, where where following notes will be notated as relative to the last note between the << and >>