What technique involves the use of a continuous rhythmic pattern and variation on the same chord?

The technique that involves a continuous rhythmic pattern and variation on the same chord is known as an ostinato. This term refers to a musical phrase or rhythm that is repeated persistently throughout a piece of music, providing a stable foundation upon which variations can occur. The repetition of this pattern creates a sense of continuity and can support melodies or other harmonic changes that occur over it.

Ostinato is often used in various musical genres, including classical, jazz, and popular music, as it allows for creativity and exploration within a set framework. It is particularly effective in establishing a groove or rhythmic drive in a composition, making it a valuable technique for composers and performers alike.

Repetition, while similar in that it involves the reiteration of musical elements, does not specifically denote the rhythmic pattern aspect inherent to an ostinato. Modulation refers to changing from one key to another and does not relate to rhythmic patterns on a single chord. Improvisation involves spontaneous creation of music rather than a specific repetitive structure like an ostinato. Thus, ostinato is the most accurate term for the continuous rhythmic pattern and variation on the same chord.