Could this be the summer Bayreuth finally sees a new Ring production that comes anywhere near its last great epic success, Harry Kupfer’s, which ran from 1988-92? If so, it’s been pipped to the post by a rather more comfortable and bijou opera house on the other side of the lake to the refuges where Wagner worked on more masterpieces – beautiful sites both, even if the “asyl” next to the Villa Wesendonck is no more..

He’s the most haunting, at times terrifying Wozzeck I’ve seen, in Richard Jones's Welsh National Opera baked-bean-factory production, and the funniest Falstaff. When we met in his dressing room at the Zurich Opera House, Christopher Purves was about to perform the central role of bitter and twisted Alberich in Wagner’s Das Rheingold, and in a week’s time you can hear him singing Handel again, another speciality at the other end of the spectrum.

Best new opera in years, they said – don’t ask who – after the Aldeburgh Festival premiere of Tom Coult’s Violet. I’d have been happy in Hackney had it been as good as, say, Philip Venables’ 4.48 Psychosis or Stuart MacRae’s The Devil Inside. Alas, nowhere near.

Will Erich Korngold, the great cinema composer, ever be recognised as a great composer for the live theatre? Probably not, at least until the prejudices that did for him in his lifetime – the prejudice against film and popular music and the prejudice against Jews – are fully corrected in practice as well as in people’s minds. Korngold, happily, is on the way back, though it has taken a long time. Die tote Stadt should, if justice be done, clinch his return.

The devil, in Verdi’s Otello, doesn’t quite have all the best tunes. Desdemona trumps him there. But the arch-manipulator Iago boasts a part of such polished, seductive wickedness that (as in Shakespeare’s tragedy) the villain can often make off with the show.

Sitting in a huge marquee on a June evening, with the sun peeking through every gap in the canopy, it is quite a stretch to imagine yourself in the remote countryside of rural Russia. But this new production of Eugene Onegin manages that, and with a minimum of means.

According to the programme, La bohème is (probably) the most performed opera, by the most performed operatic composer. Ever. So, what is it about this piece that continues to enthral, inspire and intrigue artists and audiences alike?

You don’t plan a production of a Donizetti opera without having top voices in mind. For what, after all, is his simplification of Schiller’s Mary Stuart but bel canto business as usual with a bit of high drama attached? Internationally celebrated Irish singers Tara Erraught and Anna Devin (Amy Ní Fhearraigh at some performances) are the royal cousins at deadly loggerheads. They don’t disappoint; nor do the rest of the cast, orchestra and chorus.

Handel’s operas have long posed, and still pose, severe problems for the modern theatre, and especially the modern director – all those endless streams of wonderful but emotionally more or less generalised arias hitched to interchangeable characters in fabricated love stories about crusaders or Roman emperors or oriental potentates.

Now for something completely different. The Excursions of Mr Brouček is Leos Janáček’s least typical opera and is rarely performed. Among his tragic tales such as Jenufa and Kat’a Kabanova, the charm of The Cunning Little Vixen and the strangely heart-twisting The Makropoulos Case, the Czech composer's biting satire – in which the time-travelling anti-hero is chiefly "blotto" – faces an uphill struggle for a look-in.