Nevertheless, despite her determined, almost heroic reclusiveness, the world has now found Ustvolskaya out. A dubious blessing, said her admirer Gerard McBurney, introducing Composition No 2 (Dies Irae) on Sunday evening in the latest of the Scottish composer James MacMillan's South Bank "Music of Today" concerts.
What most people seem to want to write about, McBurney complained, is the sex angle - only there isn't one. Shostakovich may have adored her and proposed marriage on more than one occasion, but she resisted him, just as she now resists photographers, espousal by women's movements, and any kind of commercial encroachment.
McBurney's frustration is easy to understand. Nothing in Ustvolskaya's extraordinary life is as extraordinary as her music. At first hearing, it tends to sound like late Shostakovich taken to extremes; then, as you check the dates, you begin to wonder who was the model and who the follower. Shostakovich himself was clear: "It is I who am influenced by you."
True, the astonishingly spare Symphony No 5 (Amen), for the unique combination of violin, oboe, trumpet, tuba, wooden cube and reciter, was finished 15 years after Shostakovich died. But Composition No 2, for eight double- basses, piano and again that wooden cube, dates from 1972 / 3, the year after Shostakovich's final, 15th Symphony, which was played in the Philharmonia's main concert later that same evening - and how consolingly human even Shostakovich's brass dissonances and percussive tappings sounded after Ustvolskaya's piled-up tone-clusters and relentless hollow thuds.
This is an extreme language: it's tempting to see its bleak, agonised, repetitive rituals as the skull beneath the sentimentally beautified skin of today's "Faith Minimalists" - the Prts, the Goreckis and the Taveners. But in essence it is utterly and only itself. The keening chants and grimacing motifs of Ustvolskaya's Fifth Symphony superglue themselves to the memory and won't be dislodged.
Kurt Sanderling and the Philharmonia's performance of Shostakovich's 15th did little to supplant them, despite one or two absorbing moments. There was some surprisingly shaky solo playing and ensemble in the first two movements, though a near-disaster from the two flutes at the heart of the Adagio seemed to jolt everyone back to attention, and things improved. Still, this was a performance with moments of insight rather than one of sustained vision.