Rhythm is the pulse of any jazz composition, whether felt or implied. It is the most critical factor in jazz styles ranging in note duration and stress. For jazz pianists, it is the difference between deciding whether to swing eighth notes or play them with equal value. While note choices often inform coloration and mood, rhythmic placement determines the feel of music. Jazz articulation emphasizes how to play rather than what is played. This chapter examines harmonic rhythm and the rhythmic components of accompaniment, including syncopation and note duration, and their use with counterpoint techniques to create rhythmic interaction in chords and chord progressions. Audio and written examples demonstrate basic styles, including swing, bossa nova, and waltz.