No round-number anniversary prompted Birmingham’s survey of Stravinsky’s complete works, the four-year IgorFest, which began last year. And though it originated as a proposal, conceived by the City of Birmingham Symphony Orchestra’s music director, Sakari Oramo, in the city’s bid to be 2008 Capital of Culture, it is that rare thing: a pure cultural initiative, unhedged by ideology, unpressured by the need to fit celebrations into a time frame.

With four years allocated to this marvellous oeuvre, there is no danger of overinsistence. Unlike the reflex observance by so many musical bodies of the Shostakovich and Mozart anniversaries, Birmingham’s approach to Stravinsky has a decorum as well as an enthusiasm that is palpably not “official”. The ambition to include every piece has not been allowed to overwhelm the orchestra’s schedules. Rather, a clutch of Stravinsky concerts lights up the season from within.

But IgorFest is not just a matter of CBSO seasons. Birmingham Royal Ballet is also involved (bringing together Stravinsky’s dance works would be a sufficient celebration), as are Birmingham Contemporary Music Group, the Ex Cathedra choir, the CBSO Chorus and the CBSO Youth Orchestra. Happy cross-city musical collaboration has been seen recently in Manchester, and Birmingham has managed it on a grand scale. It is appropriate that Stravinsky should be the beneficiary of such a disinterested aesthetic venture. His whole creative endeavour was towards the autonomy of art. He served the ideal of music as a value from which all extra-musical considerations are removed — above all the Romantic cliché of “expressiveness”.

Of course, this did not mean writing only abstract music — though he did plenty of that (the Septet and Octet are fine examples of a neo-Bachian austerity that is always captivating). It did mean that, whatever a work’s subject matter, he would compose according to exclusively musical principles of his own making. As a setter of texts, in any language, he is notorious for his disregard of spoken accent and for privileging free play with syllables over the projection of meaning. Construction was what mattered: redefining the “co-ordination between man and time”, as he put it in his early autobiography.

The CBSO and Chorus’s performance with Oramo at Symphony Hall of the Latin opera-oratorio Oedipus Rex was a reminder of how bizarrely abstract Stravinsky can be when engaged on the seemingly concrete business of telling a story. Admittedly, the outline of the Sophoclean tragedy is provided by a modern-day narrator: Michael Pennington, amplified at the rear of the platform, speaking the English translation of Cocteau’s words, which I had forgotten is by ee cummings. When the action ensues, it takes a musical form that invariably confounds us. Why these sudden strains of Verdi or Massenet or cafe music? How can such rum-ti-tum writing coexist with such choral-orchestral splendour, such lightness with such monumentality? The answer is in the constructive principle. Stravinsky admitted that he took whatever materials were at hand. His personality being what it was, though, one is less aware of the materials than of the hand holding them. The dramatic power of Oedipus Rex enters us from odd angles, but the angles are sharp and the effect is cutting. After this account, with the Australian tenor Glenn Winslade a wonderfully secure Oedipus, the Russian mezzo Ekaterina Gubanova a Jocasta of searing eloquence, and Oramo giving the decisively eccentric score his all, I felt lyrically purged indeed.

Rigorous abstraction, what Stravinsky called “syllabifying” and a breathtakingly relentless continuity governed the work in the first half, Les Noces, for all its vivid re-creation of a Russian ritual. In this performance under Thomas Adès, with the pianists Katia and Marielle Labèque, Jean-Yves Thibaudet and Kirill Gerstein, and BCMG percussionists, the chorus was the colourful, 13-strong Pokrovsky Ensemble, from Moscow, who prefaced the rendering with their own naturalistic enactment of a peasant wedding. It was instructive to realise how closely Stravinsky sticks to his source, but the Pokrovskys’ illustrative (if brilliant) directness of manner in Les Noces — they filled the stage with gesture and emoting — tended to obscure the crucial transformation that Stravinsky achieves. His wedding is an impersonal, mechanical, even anti-humanist presentation, moving because we reach through the human bustle to a timeless musical order.

It was instructive, too, to hear the CBSO Youth Orchestra at Warwick Arts Centre in Stravinsky’s Symphony in E flat, written when he was 23. He fills the formal mould clunkily. Nobody could predict his future greatness from this dutiful stuff, though Anthony Bradbury drew a feisty performance from the excellent players.