Direct octaves · Rules
Soprano and bass do not reach a perfect octave by similar motion (both in the same direction) with a leap in the soprano. It is fine if the soprano moves by step, or if the octave is reached by contrary motion.
- Direct octaves: Soprano and bass do not reach a perfect octave by similar motion (both in the same direction) with a leap in the soprano. It is fine if the soprano moves by step, or if the octave is reached by contrary motion. (Piston, ch. 3, pp. 30–32 and 35)