‘All that will be left of life will be the memory of spring storms’, muses the widow Lydia Pawlowska in Jaromír Weinberger’s Frühlingsstürme, and the publicity for Barrie Kosky’s staging at the Komische Oper Berlin described this ravishing work as ‘the last operetta of the Weimar Republic’. The first production was forcibly shut down, mid-run, within weeks of the Nazis taking power in 1933, and this latest rediscovery in Kosky’s ongoing revival of Berlin’s operetta tradition comes with weighty historical baggage. It’s also a funny, gloriously theatrical entertainment, complete with showgirls, pyrotechnics and sizzling saxophones. No living director walks that stylistic tightrope with more intelligence and verve than Kosky.

The setting is Manchuria during the Russo-Japanese war of 1905: a civilisation waltzing on the brink. This is the kind of military headquarters where society ladies host glittering balls while gunfire rattles outside, and the curtain rises on Russian officers planning strategy in a smoke-filled room, unaware that their ‘Chinese’ servant is actually Major Ito, a Japanese spy. The harassed General Katschalow has to deal not only with his headstrong daughter Tatjana, but a snooping journalist and his own unrequited love for Lydia – who, in turn, loves Ito.

So there’s ample scope for misunderstanding, both comic and tragic, and Weinberger’s score – reconstructed and arranged by Norbert Biermann – can turn on a pfennig from high-kicking foxtrots to an iridescent late-Romantic yearning that Kosky compares to Schreker (I heard hints of Weinberger’s teacher Novák, too). Bittersweet doesn’t begin to cover it and Kosky takes his cues from the score.

Dance routines are exuberantly staged – cue tennis racquets, dragon dancers and Busby Berkeley showgirls with ostrich-feather fans – and he’s not afraid to go for belly-laughs either. You don’t need to be a native German speaker to enjoy Stefan Kurt’s rubber-faced performance as General Katschalow (a non-singing role), although opera buffs of a sensitive disposition should look away when he attempts Lensky’s aria from Eugene Onegin. He’s a droll counterpart to Alma Sadé as Tatjana and Dominik Köninger as her sweetheart Roderich; their bright, agile voices are well suited to the sparkier numbers, generating screwball comic energy.

But Frühlingsstürme pivots on the doomed romance of Lydia and Ito, a role originally created for Richard Tauber and clearly modelled on Prince Sou-Chong in Lehár’s Das Land des Lächelns. War, not culture, is what divides Weinberger’s lovers, and although Ito gets a real lollipop of a Tauber-lied in Act 3’s ‘Du wärst fur mich die Frau gewesen’, what really lingers in the memory are the score’s haunting waltz-songs. Neither Vera-Lotte Boecker as Lydia or Tansel Akzeybek as Ito has what you might call a luxurious voice, but their mobile, articulate phrasing is stylistically appropriate and they have enough tonal warmth to make their big moments soar. They make an attractive, wholly sympathetic pair: the moment in Act 2 when the camera drifts with them across the stage as bleak reality dissolves into an MGM vision of sweeping staircases and swaying dancers is pure magic.

Kosky’s directorial balancing act is elegantly supported by Klaus Grünberg’s atmospheric, deco-influenced designs (deep shadows and paper lanterns), Otto Pichler’s choreography and an orchestra under Jordan de Souza that plays this long-lost music as sensuously as if it was Strauss (R) and as brilliantly as if it was Strauss (J). If the third act drags slightly – and if the poignant farewells at the very end (partly an invention of Kosky and his team) tip the scale a little too far towards melancholy – these are forgivable weaknesses. Kosky’s Berlin operetta productions have been among the most significant operatic events of the 21st century; incredibly, this is (I believe) the only one so far to have been released on disc in any form. I can’t imagine a better demonstration of why this genre matters – or a more enjoyable one.