Reconstructed from fragments in D Major by Nicholas Cook.
Piano Concerto No. 6 in D major, Hess 15, is an unfinished piano concerto built on fragmented score.
In 1815,Beethoven spent a great deal of time working on a piano concerto in D major, which would,if completed, have been the sixth. He made about seventy pages of sketches for the first movement. He even started writing out a full score which runs almost uninterrupted from the beginning of the movement to the middle of the solo exposition. The scoring becomes patchy as the work goes on and there are signs of dissatisfaction. Beethoven abandoned the work and this partial movement (known as Hess 15) remains one of the most substantial of Beethoven's unrealized compositions.
A completion of the first movement was reconstructed by British scholar Nicholas Cook in 1987.
This concerto movement contains many ideas and may foreshadow the first movement of the Ninth Symphony in many of its themes.
Why did Beethoven abandon it? A number of reasons might be deduced. Perhaps he planned it for the cancelled benefit concert of 1815 or maybe he intended to play the solo part himself and abandoned the project when his deafness made this impractical. The piano part comes across as decorative to a symphonic argument.