String Quartet No. 2 (Tchaikovsky)
From Wikipedia, the free encyclopedia

The String Quartet No. 2 in F major, Op. 22, by Pyotr Ilyich Tchaikovsky, was composed between December 1873 and January 1874. It premiered on 22 March 1874.[1]
In October 1874, Tchaikovsky got on record as considering it his finest work: "I regard it as my best work; no other piece has poured forth from me so simply and easily. I wrote it almost at one sitting." (from letter to his brother Modest, quoted in reference[2]). Also, later (quoted in the chapter '1879-1881'), "I wrote that music (Vakula) with affection and with delight, just as I did... the Second Quartet" (from letter to Nadezhda von Meck, ibid).
The string quartet is in four movements:
The first movement starts with an 18-bar slow introduction without key signature in 6
8 time, with the character almost of a cadenza with increasingly rococo embellishment. This leads to the main body in 4
4 time.
The second movement is in a mixed meter. It mostly follows a pattern of 2 bars of 6
8 + 1 bar of 9
8 pattern, occasionally augmented to 3+1 and 4+1. After that, there is a A major middle section in 3
4 marked l'istesso tempo, followed by a return to the asymmetrical 2+1 complex tempo. As tension mounts at the end, the pattern is stretched to 14+1.
The third movement is in 3
4 time with a middle section marked pochissimo più moto.
The fourth movement is in 3
4 and is relatively uncomplicated.