Piano Sonata No. 1 (Chopin)
The Piano Sonata No. 1 in C minor, Op. 4 by Frédéric Chopin was written by the composer in 1828 (probably begun around July). It was written during Chopin's time as a student with Józef Elsner, to whom the sonata is dedicated. Despite having a low opus number, the sonata was not published until 1851, two years after Chopin's death, by Tobias Haslinger in Vienna. This sonata has been highly underestimated, both musical difficulty and quality. 
The sonata has four movements:
- Allegro maestoso in C minor — It is in the form of a sonata. Only in the aspect of key relations does this movement break from tradition - the second group of themes is based in C minor as much as is the first, so that the dramatic contrast of key which Cedric Thorpe-Davie among others identify as the heart of sonata form is lost. Furthermore, the recapitulation begins in the remote key of B-flat minor, with the second theme appearing in G minor.
- Menuetto in E-flat major — This is the only known minuet that Chopin wrote.
- Larghetto in A-flat major — This piece is set in 5
4 time, which is very unusual for pieces of that era. The 3rd beat of each 5-beat bar carries a secondary accent, which is marked explicitly in certain bars. In other places, it can be inferred, and in still other places Chopin seems to defy this convention and not expect this. James Huneker, in his introduction to the 1895 American publication of the Mikuli edition of the work, calls this unusual characteristic a "failed novelty."
- Finale - Presto
Of Chopin's works, this is among the least recorded.
- According to the Chopin chronicle site.
- Later editions, like Breitkopf & Härtel (1880), and Augener (1882), explicitly label it as "nachlass" or posthumous.
- Grande Sonate pour le Pianoforte composé par Frédéric Chopin. Oeuvre 4 (Nº8147 ed.). Vienna: Tobias Haslinger. 1851. p. 31.
- "Fryderyk Chopin - Information Centre - Other dances - Genres". Fryderyk Chopin Institute. Retrieved September 20, 2014.