where does the cadenza usually occur in a concerto
Cadenza The term cadenza often refers to a portion of a concerto in which the orchestra stops playing, leaving the soloist to play alone in free time (without a strict, regular pulse) and can be written or improvised, depending on what the composer specifies. Sometimes, the cadenza will include small parts for other instruments besides the soloist; an example is in Sergei Rachmaninoff's Piano Concerto No. 3, where a solo flute, clarinet and horn are used over rippling arpeggios in the piano. The cadenza normally occurs near the end of the first movement, though it can be at any point in a concerto. An example is Tchaikovsky's First Piano Concerto, where in the first five minutes a cadenza is used. The cadenza is usually the most elaborate and virtuosic part that the solo instrument plays during the whole piece. At the end of the cadenza, the orchestra re-enters, and generally finishes off the movement on their own, or, less often, with the solo instrument.
Johann Sebastian Bach Bach enriched established German styles through his mastery of counterpoint, harmonic and motivic organisation, and his adaptation of rhythms, forms, and textures from abroad, particularly from Italy and France. Bach's compositions include hundreds of cantatas, both sacred and secular.[3] He composed Latin church music, Passions, oratorios, and motets. He often adopted Lutheran hymns, not only in his larger vocal works, but for instance also in his four-part chorales and his sacred songs. He wrote extensively for organ and for other keyboard instruments. He composed concertos, for instance for violin and for harpsichord, and suites, as chamber music as well as for orchestra. Many of his works employ the genres of canon and fugue.