Shostakovich was extremely lucky in at least one respect: in his declining years he married a woman who was perfect for him, both during the remainder of his life and also for his posthumous legacy. In the half a century since the composer’s death, Irina Antonovna Shostakovich has been funding archival research and other scholarship, and publishing painstaking editions of Shostakovich’s scores. We can appreciate the results of her work by comparing the orderly state of her husband’s Nachlass with the chaos that still reigns over Prokofiev’s scores – there is no complete, accurate edition even in the pipeline. There has also been a public demand for every scrap from Shostakovich’s creative kitchen, in the hope that these will give us access to the mind of this conflicted genius. The present album – a project masterminded by the pianist Nicolas Stavy – is a testament to this, and it stands as a labour of love. The beautifully prepared cover reproduces the composer’s manuscript score of Symphony No 14’s unmistakable ending. The excellent and fully up-to-date notes are by Elizabeth Wilson. The performances themselves are masterly, the interpretations highly persuasive.

It could be said that some of the material is of more historical than musical interest, but since this is Shostakovich, the distinction may be moot. Not long after the Bolshevik takeover, he wrote a march for the victims of the Revolution, and since this is mentioned in every biography, it is good to hear it at last, although it sounds much as we might have expected. There is a fragment of Shostakovich’s piano-duet transcription of Mahler’s Tenth Symphony, and another fragment from a promising but abandoned violin sonata of 1945. There are also some early piano pieces, of which the Bagatelle leaves the greatest impression for its energy and unusual texture.

But the main focus of the programme is the composer’s own chamber arrangement of Symphony No 14 for voices, piano, celesta and percussion, which rises artistically above its practical purpose. The Fourteenth, from 1968, is a bleak song-symphony in 11 movements, all meditating on death. The style is sparse, modern and uncompromising and it is actually wonderfully effective in this pared-down ensemble. The deftly chosen percussion timbres, with xylophone, castanets, tom-toms and woodblock, transforms what could merely have been a piano reduction into a genuine alternative concert version that may now be revisited by other musicians. The two singers, soprano Ekaterina Bakanova and bass Alexander Stavrakakis, are magnificent. Bakanova is powerful and intimidating in the ‘Malagueña’ (No 2), and ‘On the Watch’ (No 5) is engrossing for her changes of timbre. Stavrakakis has a beautiful lyrical voice, which he deploys with great intensity and subtlety in No 7, ‘In the Santé Prison’, but he is equally capable of conveying sarcasm and power in No 8, ‘The Zaporozhian Cossacks’. Both demonstrate their crystal-clear delivery of the Russian text even in the tongue-twisting ‘Lorelei’ (No 3). Stavy’s piano-playing is decidedly orchestral, with plenty of verve and character. The ending is shattering, just as it should be.