An important rhythm technique used in many styles of music is the Percussive Strum. This is achieved by forming a chord shape with the left hand and placing it on the strings, but without pressing down on the frets.
A percussive strum is indicated by using an X in place of a notehead. This technique can be applied to any type of chord. Listen to the following example on the recording to hear what the percussive strum sounds like when applied to Root 5 power chords.