Contrary octaves

1. What are contrary octaves?
2. What is an octave by contrary motion?
3. Are contrary octaves OK?
4. Are direct octaves allowed?

What are contrary octaves?

To my understanding a direct octave is when there is an octave followed by another octave going in the same direction (descending or ascending). A contrary one is when their is an octave after another one but they are going in opposite directions.

What is an octave by contrary motion?

Standard wisdom has it that, in conventional harmony, consecutive octaves are illegal, whether the parts move in similar motion or in contrary motion (e.g. for the latter, two notes a fifteenth apart moving to an octave, or an octave moving to a unison - or indeed vice versa).

Are contrary octaves OK?

Two octaves in a row are also considered bad. call this 5ths or 8ves “by contrary.” The two “rules” really boil down to the same thing: no two 5ths in a row, and no two 8ves in a row.

Are direct octaves allowed?

A venerable rule of traditional Western part writing is the so-called Direct Octaves Rule (also known as Hidden or Exposed octaves), whereby similar pitch motion (i.e., two or more voices moving in the same direction) to a perfect octave should be avoided unless step motion is used.