Show off your theory chops with my weekly challenge! You’ll find a new question here every Monday. Please comment to post your reply.
This week’s challenge:
Below is one of Beethoven’s last and greatest utterances: the opening fugue from his C-sharp Minor String Quartet, Op. 131. The subject melody is in blue, and the answer is in red. What’s unorthodox about this fugue’s answer?

Reply to post your answer, and check back on Friday, October 15 to see if you’re right!
ANSWER for 10/11/21
This fugue’s answer is in the key of IV, the subdominant. It’s in F-sharp minor. The more standard key for an answer would be V, the dominant (G-sharp minor in this case). But by having the answer in the subdominant, Beethoven avoids a more typical emphasis on the V–I relationship. J. S. Bach’s Toccata and Fugue in D minor is an even more famous example of an answer in IV instead of V.
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Not having a great knowledge of fugue theory, I’ll take a guess.
The answer starts on the tonic C# after the subject starts on the fifth. Is that special? I don’t know.
Also, the answer starts after the subject ends. Again, anything?
When I don’t know the Orthodoxy, I can only observe and report. It was kind of fun. Thanks, Aron.
Hi Pat! You’re on the right track, and I love how carefully you’re looking at the music! Typically the answer does begin after the subject concludes, so that’s pretty standard in a fugue. But what key is the answer in, compared to the key of the subject? 🙂
The answer is in F-sharp minor… Assuming the subject is in the natural minor mode, I can’t see any incongruity in the pitch collection. Is it because the answer is a 4th, and not a 5th, from the subject?
Oops, except for the D-natural in the answer…
And I meant to say “melodic minor”! I’ve only had one cup of coffee…
I think that traditionally the answer comes in at a fourth below instead of a fifth-but saying that, I can suddenly think of lots of exceptions.
Hey Randy, you’re on the right track! Think in terms of key: the subject is in the key of I, and the answer is traditionally in the key of…
The answer is usually in the key of V, but this answer is in the key of IV, which can happen but less often. So the subject is in C# minor while the answer is in F# minor. I do know that by the end we are in C# Major.