Erik Chisholm: Piano Concertos 1 & 2HyperionThis little-known Scots composer was either a wacko wanderer or some kind of secret genius: you’ll have to decide for yourselves. All I can judge with certainty from these two illuminating retrievals is that Chisholm had a rare ability to make an arresting opening statement and a quirky knack of taking your ears to places they had never expected to visit.A Glaswegian, taught by Russians, Chisholm (1904-65) gave the Scottish premiere of Mussorgsky’s Pictures at an Exhibition before heading east and south. He served in Asia during the Second World War, founded an orchestra in Singapore and spent the rest of his life as Dean of Music at Capetown University.His first concerto, titled "Piobaireachd," takes its title from Highland bagpipes and its opening theme from a popular lament for a dead cow. Oboe and bassoon do the pipey noises. Sniggers aside, it’s a haunting sound and Chisholm develops the material over four movements with constant invention and no slippage of concentration. You might wonder why he didn’t introduce real live bagpipes to the orchestra; probably, because it would have killed off the two front rows and blown out all the windows.The second concerto, "Hindustani," is founded on an Indian raga and struggles rather to adjust its meditative properties to western orchestral colours. At best, it’s sub-sub-Bartók. Danny Driver is the adventurous pianist and the BBC Scottish are conducted by Rory Macdonald, with Peter Thomas doing some melismatic concertmaster solos. Not an essential addition to the sum of human experience, perhaps but well worth a second listen. Chisholm warrants at least one hearing at the BBC Proms.Some more side-tracks1600 NaïveWhat on earth was going on in music at the dawn of the 17th century? Rinaldo Alessandrini’s Concerto Italiano provides a set of pieces by Gabrieli, Frescobaldi, Bononcini and others more obscure, fizzing with mischief and dance. The sheer playfulness of the music blows a welcome hole in the ensuing classical solemnity.PisendelRaumklangJohann Georg Pisendel (1687-1755) - you knew those dates, right? – led the Dresden orchestra in Handel’s time and wrote a cheeky G-major concerto for himself. Paired with pieces by Fasch, Heinichen, Telemann and Handel, it holds up well. Johannes Pramsohler leads the buzzy little group of International Baroque Players.Maurice Ohana: Etudes d’interpretation LMGOhana’s career was blighted by the political dominance of French modernism by Pierre Boulez. A Gibraltarian Jew, sceptical and progressive, he wrote on the edge of atonality without subscribing to dogma. These piano pieces, played with a rapturous tingle by Maria Paz Santibanez, fall midway between De Falla and Webern. Original thoughout and thought-provoking.Frederic Rzewski: The People United will never be DefeatedPiano ClassicsAn American in Rome, Rzewski wrote these 36 piano variations in 1975 as a tribute to the Allende socialist government in Chile, toppled in a US-backed military coup. He dedicated the piece to Ursula Oppens, who compels attention in this authoritative performance. At the sixth variation, the tension is so high you may need to walk around the block before taking in the seventh.___Norman Lebrecht is a regular presenter on BBC Radio 3 and a contributor to the Wall Street Journal, Bloomberg and other publications. He has written 12 books about music, the most recent being Why Mahler? He hosts the blog Slipped Disc.