MUSIC / A funny thing happened to Joseph H

How do we spot a classic? With Mozart and Beethoven, the answer's already there. But what about those other composers whose works are ignored? For that matter, what about Joseph Haydn?

Standard concert items generally leave the question in its rhetorical form, but QEH visitors found a pair of exceptions last week: the Symphony in G, Op 24 No 3 by Carl Stamitz, played on Thursday by the London Mozart Players, and Haydn's Piano Concerto in G, given by the visiting Deutsche Kammerphilharmonie Bremen with the pianist Mikhail Pletnev on Saturday.

This Stamitz was the son of Johann, founder of the "Mannheim School" which so impressed Mozart with its standards of orchestral discipline. Mannheim mannerisms included sudden dynamic changes and strong dynamic shadings, both used to powerful affect in this symphony. Surprise was of the essence, not only in the first movement with its avoidance of textbook sonata patterns, but also in the finale, a riotous folkdance that took the plunge straight after a lame Andante.

Eminently theatrical, these moves gave vigour to a bland, gallant idiom, and were tastefully done - in contrast to the reckless ploys of Beethoven's Symphony No 1. In a sharply etched performance, beautifully executed under the baton of Matthias Bamert, this rarely heard work sparkled with wit and energy. While Stamitz tickled the ears, Beethoven bent them to his purpose, sure of the strength of his symphonic logic to prevail.

The pianist Justus Frantz gave a vision of classical poise in Mozart's last concerto, K595, itself refined and sober in contrast with Pletnev's account of the D minor Concerto, K466, directed from the keyboard two days later. A green carnation would have matched his dandyish manner, choreographed to the Kammerphilharmonie's every action, and best ignored for a proper awareness of the music's depths and the superb control of touch and colour in his playing. Each phrase, chord and counterpoint seemed precisely judged, with nothing left to chance. Yet the impression was of spontaneous invention, reaching a romantic climax in the finale, the Bremen players alert and responsive partners to his flamboyant reading.

And, in the Haydn concerto, his flawless accuracy and tone belied the conventional wisdom that this composer's keyboard parts are dull. Apart from the cardinal sin of expecting it to sound like Mozart, this music is imperishable. But whereas Mozart composed in symmetries, Haydn's way was to try the experiment - and his surprises, unlike those of Stamitz, must always be heard as part of the argument. In the first movement, the harmonic guile and myriad ways of entwining soloist and orchestra were a source of constant amazement, while the relaxed Adagio for oboe and muted strings was music for a summer night. The Finale played the usual Haydn fun and games right up to the unpredictable conclusion. With third- rate Rococo revived daily by the yard, why is so much Haydn excluded from the repertoire? There must be an answer.

Nicholas Williams