Now that the maverick Russian pianist Grigory Sokolov has become a flavour of the month among piano connoisseurs, digging out ancient recordings by him has become a trend. This one goes back to November 1975, when he recorded one of the most challenging sonatas in the piano repertory at the age of 25. I was not initially convinced by his first movement, whose bursts of anger are not quite integrated into the complex structure. But through the short scherzo and the extended adagio sostenuto the playing deepens, and by the final fugue, Sokolov is in overdrive, achieving a dazzling mixture of utter clarity and profound expression through the tortuous writing.