Yes, you can pick holes with aspects of Valery Gergiev's sprawling year-long centenary survey of the Shostakovich symphonies - and indeed with the symphonies themselves. Yet this week's concluding concerts, with Gergiev conducting his own Mariinsky Orchestra and Chorus from St Petersburg, have set the seal on the musical highlight of the year.

The final two concerts each paired a "problem" symphony with a more established one, and though it was clear the long-established and highly personal Tenth Symphony is a greater work than the Twelfth, and the underestimated Eleventh more enduring than the Second, these rarely performed lesser works are crucial to a rounded appreciation of the composer.

Not even Shostakovich's greatest admirers would say the Twelfth, subtitled The Year 1917, is a high point in his output. Yet the bleak restraint of the slow second movement was fine by any standards. And who is to say that a conservative work from 1961 such as this has not stood the test of time better than much of what was written in those years by others in more advanced idioms?

The real curiosity, though, was the one-movement Second Symphony from 1927, a fascinating failure but a prime example of the openness of the Lunarcharsky era in Soviet culture. It was heavily influenced by Berg's Wozzeck, which had reached Leningrad that year. No Shostakovich symphony is more consciously experimental than this, with its feverish dissonances and agitprop factory sirens out of which emerges a choral hymn to Lenin.

Gergiev's artistic generosity allowed each symphony to make its own case. He was thrillingly assisted in this by his Russian orchestra, with its big, bold and idiomatic sound. The Tenth Symphony, in particular, benefitted from this rawness. The musicians had only had a day's rest from their back-to-back Cardiff Ring Cycle, where the playing was said to be uneven, but with Shostakovich they were on home ground. You will wait a long time to hear these pieces played with greater excitement or commitment.