# How much oblique motion is allowed in 3 part counterpoint

I have done a new counterpoint exercise today using 3 parts but I ended up with quite a lot of oblique motion and it got me thinking that I actually don't know what the restrictions are on using oblique motion in the first place so could someone please clarify? Is what I have done ok?

My textbook does nothing to explain limitations on use of oblique motion and I did a search through other documents that totally avoided the topic too. My primary questions are:

1. can you use oblique motion on two upper voices twice in a row with a moving bass? (see chord 3 & 4)
2. How many times can a single voice be repeated in a row if the other voices are moving in contrary motion? (See chords 8,9 and 10)

These are very specific & vital questions and seeing as everything else is so "by the book" in counterpoint, there should be clear answers somewhere

EDIT: The CF is the bottom voice

• I'm not aware of a restriction on oblique motion, but I question the use of so many repeated notes in the middle voice and of three Fs in a row in the upper. It might inform potential answers to know which voice is the cantus firmus. Commented Mar 11, 2021 at 17:10
• thanks for the tip Aaron. I wasn't aware it would help but I have included the information above
– user35708
Commented Mar 12, 2021 at 7:35

When you do species counterpoint exercises like this you should be working from a book which should give you the rules and guidelines.

Generally, I think you can give a rule of thumb of to don't do any particular thing more that two or three times in a row. Don't repeat a note more than three times, don't use the same interval more than three times (this is the one I'm thinking of from Fux, parallel thirds are ok, but no more than three in a row), etc. etc.

If the limit for repeating a note is three, then the limit for oblique motion must be twice. To move obliquely a third time would mean the held note is repeated a fourth time which would be way too much repetition!

Aside from certain strict rules like no parallel fifths, end with a clausula vera cadence, etc. the general goal is variety of motion and independence of parts.

• Thanks Michael. I read my text book and other texts but none made any mention of oblique motion specifically. I have updated my question too so please have a lookT.
– user35708
Commented Mar 12, 2021 at 7:40
• Admittedly my last class in counterpoint was fifty years ago, but I don't remember any specific rules about oblique motion either. Commented Mar 12, 2021 at 11:28
• In Mann's The Study of Counterpoint, the English translation of Fux, these things about relative motion and repetition are covered on pages 21, 22, and 29, mostly in footnotes where Mann restates Fux's intentions in a more quantitative way. The sections are motion types in the very beginning of the text and fig. 5, Aloysius' first exercise. It isn't stated specifically as a limit on oblique motion, but rather in terms of limiting repeated notes. The limit on repeated notes limits oblique motion by necessity. Commented Mar 12, 2021 at 14:01
• The Fig 5 footnote is most explicit. It basically says don't repeat a note more than twice, therefore there should not be more than one move by oblique motion consecutively. That limit on repetition does not seem to change in the section on three part writing. Commented Mar 12, 2021 at 14:10
• Of course when looking at the ligature the motion is all oblique. So, the points above about limiting repetition are specifically about oblique motion where one of the voices stops moving. Again, the point is really a limit on repeating notes in a line. The concern isn't too much oblique motion, but lines that stop moving. Each line should be a melody not a drone or pedal point. Compare Fux's examples with organum. That contrast in texture should give you an idea of the "variety of sound" laid out by Fux as the goal. Commented Mar 12, 2021 at 14:20