Edinburgh Festival DVORAK'S THE JACOBIN Festival Theatre

The blurb on the festival leaflet was selling Dvorak's The Jacobin as "charmingly light-hearted". Those who turned up in the expectation of an evening of rosy-cheeked good humour would have been disappointed. For all its hilarity, and there are some wonderfully funny moments in this piece, The Jacobin is for much of its length very dark indeed. And this is where its success lies: the love making of Jiri and Terinka would have little spice were it not under the threat of frustration at the hands of vengeful authority, and the homecoming of Bohus, the supposed "Jacobin" of the title, would be all flabby nostalgia but for the fact that he is in danger of his life. Marie Cervinkova-Riegrova's libretto is among the best in the Czech tradition. Dvorak's score turns it into a masterpiece.

Christine Mielitz's production opts for the less easy path of focusing on the tougher aspects of the opera. A prevalent image is one of a benevolent but impotent aristocracy being supplanted by a thuggish new regime. Dvorak's score can take this and the cliff-hanging end of the second act is all the more powerful for it. Against this background the humour had genuine bite and the drama stayed on a knife edge.

The role of the chorus, a vital protagonist in Czech opera, is much enhanced: at times they were jolly enough villagers, at others a cold blast of verismo turned them into a threatening rabble. This thoroughness of observation extended to the final ballet (how much easier and damaging it would have been to cut it) which was played as an allegory of frigid nobility being warmed up by a jolly crowd of children and peasants - a marvellous bonus.

The main problem with the externals was Reinhart Zimmerman's implausible set - a kind of sci-fi underground landscape in which silvery rock faces trundled aimlessly around. The appearance of a desolate Caspar David Friedrich landscape in the final moments seemed to be telling us that all we had seen had been played out beneath it. Whatever the intention, it didn't manage to subvert the atmosphere of small town intrigue, which a uniformlymagnificent cast supplied in buckets.

Their level of insight aided by a snappy translation (Simon Rees) allowed the drama to unfold at a gripping pace. Richard Coxon's superbly focused Jiripaired off memorably with Claire Ruytter's wittily sung Terinka. Rita Cullis's Julie was a model of fortitude; Peter Sidhom's Bohus went more for passion than dignity, but captured the hearts of all in his show stopping song in act two.

Donald Maxwell's portrayal of the odious Filip, will, with a few more tucks, be one of the great comic turns of the season and both Alasdair Elliott (the schoolmaster) and Stafford Dean (the old Count) made the best of their vivid roles.

Equally persuasive was the chorus, with everyone singing with affecting enthusiasm. Best of all, however, was Richard Armstrong's effortlessly idiomatic reading of Dvorak's score. Here is a conductor who understands the subtle rhythms and textures of the composer's operatic manner in which acres of exquisite detail illuminate the drama with an insouciance that might have made Richard Strauss jealous. Set design apart, Scottish Opera's new Jacobin gives Dvorak's wonderfully human semi-comedy the treatment it deserves.