Oblique motion occurs when which of the following describes voice-leading?

• A. One line moves while the other stays the same
• B. Both lines move in parallel motion
• C. One line stays the same while the other moves
• D. Both lines stay the same

Answer: (C)

Oblique motion describes a voice-leading situation where one voice holds its pitch while the other moves to a different pitch. This creates a fixed common tone between the two lines as one part remains steady and the other changes. It’s different from parallel motion, where both voices move in the same direction, and from situations where both voices stay on the same note (no motion). So the description that one line stays the same while the other moves best captures oblique motion. For example, if the soprano holds C while the bass moves from E to F, that demonstrates oblique motion with a sustained note in one voice and movement in the other.