Rebus - Markevitch Piano Concerto in B flat - Mozart Symphony No 3 - Schumann Gerhard Markson, incoming principal conductor of the National Symphony Orchestra and tutor on the Dublin Master Classes International Orchestral Conducting Course, took over briefly from the young conductors who were given their moment of glory at the National Concert Hall last Friday. Seven of the 10 course participants had been chosen to conduct the NSO in works by Markevitch, Mozart and Schumann. But it was Markson who stepped up for the opening of Schumann's Rhenish Symphony, to demonstrate the extent of the influence a conductor can have without rehearsal over tempo and tempo changes. Tempos and tempo changes are, no doubt, issues that young conductors are likely to worry about. But an even greater concern has to be the extent to which they accept exactly what an orchestra offers. The general thickness of sound in Schumann's Rhenish Symphony, the lack of air and limited rhythmic spring in Mozart's final piano concerto suggested that these particular young wielders of the baton tended to accept too much. The seven came from extremely diverse backgrounds, Chris Younghoon Kim from Korea, Michal Dworzynski from Poland, Marion Wood from Australia, David Rahbee from the US, Claus Efland from Denmark, and Gavin Maloney and Cathal Garvey from Ireland. Kim, who conducted the 19-year-old Igor Markevitch's Rebus of 1931 in its entirety, had perhaps the easiest task. This mechanistic music has a built-in roughness, which Kim's directness of approach highlighted to advantage. Markson's choices of Mozart and Schumann (neither of whom the NSO frequently plays with much distinction) provided altogether more awkward challenges, which Michal Dworzynski (in the first movement of the Mozart and the last two of the Schumann) and Gavin Maloney (in the second movement of the Schumann) seemed to make the most headway in solving. Andrei Roudenko was the fluent if not particularly Mozartean soloist in the concerto.