So precise in its emotional colours, so clear in its levels of subtext, so innately itself in every gesture, Debussy's opera Pelléas et Mélisande is nevertheless endlessly interpretable, by conductors, singers and stage directors. The situation could hardly be simpler. Pelléas is a prince, in the lost realm of Allemonde, and Mélisande the new young wife of his elder half-brother Golaud. The two fall in love, or more drift. Golaud's jealousy mounts—frighteningly, as he forces his young son Yniold to spy for him and violently challenges Mélisande in the presence of his aged grandfather, Arkel. He kills Pelléas, whereupon Mélisande declines, via childbirth, into death.

Welsh National Opera 1992

Not quite. Or perhaps not yet quite. What was widely expected to be one of the year's outstanding operatic occasions was indeed an evening of many marvels, but there was a sense at Friday's opening performance in Cardiff of a production still moving loudly in the clanks and bangs of the scene shifting towards a possibly glorious fruition, and a sense of great minds thinking not wholly alike.

First of those great minds is, of course, that of Pierre Boulez, and it is a proud coup for Welsh National Opera to have secured him to conduct his first new opera production since the premiere of the three-act Lulu in Paris in 1979. Ten years before that he conducted an intensely remembered production of Pelléas at Covent Garden, one that placed Debussy's opera in a momentous realm between Wagner and Wozzeck, between sweeping magnificence and sudden gestures of shock and violence. This is still where we are.