Incorrect- Chopin's mazurkas are at a very low level of virtuosity. They may even be on the lowest scales of difficulty (I don't know the rating system exactly). Here are a few of the easiest, yet great, mazurkas:
C# minor (not sure which #)
Op. 30 #1 in C minor
Op. 24 #2 in C (a little harder, but my favorite- it's kind of spooky/mysterious)
Op. 63 #2
Ab major (#?)
Op. 33 #1 in G# minor
There are also a few easy preludes, which include:
#9 (my fav, it's beautiful and is a good study of chords), #6, #15 (a bit harder), #4 (another chord structure piece, but is harder)
Did you know that Chopin also wrote a fugue (A minor)? You may want to find this piece, though I don't know much about it.
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As I said more than once in this particular thread:
You get a 9-10 year old who knows nothing of piano, who is not particularly talented and who does not have a natural co-ordination - in other words - a completely normal kid. S/he is not very interested in music either, but has come to you for his/her first piano lesson. S/he is curious, but not overwhelmed by the prospect of learning the piano.
This is his/her first lesson, and I believe it is important that s/he goes out of the lesson knowing how to play a nice tune, something that will have to be taught by rote, but that will make him yearn for more.
Have you got the picture now? I have over the years selected a very small number of such pieces (they are in the first post). Most pieces that would serve this purpose are unbelievably dull (yes, I am talking Bartok Mikrokosms, book 1 - sorry Bartok fans. And you can include Kodaly there too. For all his cleverness he is dull, dull dull).
So are you telling me that in such a situation you would use your first half hour lesson to teach this 9-10 year old a Chopin Mazurka? that he would be really excited about Prelude no. 9?
I don't think so.
Just to give you an idea of what we are talking about, here are the ABRSM grades for each of the pieces you suggested (it should a student 2 years to do grade 1, 3 years for grade 2, 4 years for grade 3 and so on)
C# minor (These are the C# minor mazurkas: op. 6 no. 2 and op. 63 no 3 are grade 7; Op, 41 no. 4 is grade 8 and op. 30 no. 4 and op. 50 no. 3 are both above grade

Op. 30 #1 in C minor – grade 6
Op. 24 #2 in C - grade 6
Op. 63 #2 – grade 6
Ab major (These are the Ab major mazurkas: Op. 24 no. 3 is grade 6. Op. 7 no. 4, op, 17 no. 3, op, 41 no. 3, op. 50 no. 2 are all grade 7. Op. 59 no. 2 is grade

Op. 33 #1 in G# minor – great 6
Preludes
#9 – grade 6
#6 – grade 6
#15 – grade 7
#4 - grade 5
An orthodox, ABRSM teacher (which I am not), would consider assigning these pieces after 7 - 8 years of piano study.
By the way, here are the easiest Mazurkas (grade 5):
No. 9 in C major (op. 7 no. 5)
No. 48 in F major (op. posth. 68 no. 3)
No. 49 in F minor (op. posth. 68 no. 4)
And the easiest preludes (again grade 5)
No. 4 in E minor
No. 7 in A major
No. 20 in C minor (that one will really cheer total beginners with its catchy tune and dancing rhythm! By the way I’m being sarcastic)
Apart from that you have (all grade 5)
Waltz no. 17 in A minor
Waltz no. 18 in Eb major
Cantabile in B flat major
Feuille d’album
So I stand by my assertion. Chopin did not write any easy piece. If they are not difficult technically they are difficult musically.
Yes, these pieces may be easy in the context of Chopin’s other pieces, or in the context of music in general, but they are not easy at all if your client is a total beginner.
Even though they may not be virtuosic, you need a student who is mature musically to tackle them. According to the ABRSM this would mean someone who had been studying the piano for some 5 – 6 years. Even I, who rarely go by the ABRSM book would not think of assigning Chopin before 2 years study.
Have a good look at the score of Martha Mier’s Busy fingers (suggested by Minsmusic somewhere in this thread). You can get it at the Alfred’s website. This is what I am looking for.
Nevertheless I am grateful for you taking time to suggest pieces that although inappropriate for a total beginner in his first lesson I may consider for an intermediate student.
Finally. Chopin’s fugue. Yes I know this work quite well. Have you ever listened to it? I doubt anyone would say it is by Chopin. Then again he loved Bach. It is not very difficult (grade 7) – although completely inappropriate for a beginner. It is a two –voice fugue with a six bar theme, stretto, partial entries and all that you have come to expect from a Bach’ fugue. It was composed in 1841 – 1842, and the score is published in the volume of minor works of the Paderevsky edition. Ashkenazy recorded it for Decca.
Best wishes,
Bernhard.