Editing Counterpoint (section)

===Fourth species===
In ''fourth species'' counterpoint, some notes are sustained or ''suspended'' in an added part while notes move against them in the given part, often creating a [[Consonance and dissonance|dissonance]] on the beat, followed by the suspended note then changing (and "catching up") to create a subsequent [[Consonance and dissonance|consonance]] with the note in the given part as it continues to sound. As before, fourth species counterpoint is called ''expanded'' when the added-part notes vary in length among themselves. The technique requires chains of notes sustained across the boundaries determined by beat, and so creates [[syncopation]]. A dissonant interval is allowed on beat 1 because of the syncopation created by the suspension. While it is not incorrect to start with a half note, it is also common to start 4th species with a half rest.
<score sound="1">
\relative c' {
\new PianoStaff <<
\new Staff {
\set Staff.explicitKeySignatureVisibility = #all-invisible
a'2 d~ d c~ c bes~
\key d \minor bes
a b cis d1 \bar "|."
}
\new Staff {
d, f g f e d \bar "|."
}
>>
}
</score>Short example of "fourth species" counterpoint