The Third String Quartet was Shostakovich’s only composition during the year 1946. He dedicated it to the members of the Beethoven Quartet, who gave the first performance in Moscow on their namesake’s 176th birthday, December 16, 1946. The mention of Beethoven is apt, for many observers have felt that this quartet, particularly in its heartfelt fourth movement, consciously evokes the spirit of the older master. Yet the Third String Quartet is no imitation. In fact, this is a wildly original composition.

One of the best things about Shostakovich was his utter unpredictability. He had greeted the end of World War II the previous year not with the victory symphony expected by Soviet officials but with a Ninth Symphony full of high spirits and a sort of in-your-face cheekiness. Now, in the first full year of peace, he turned to the form that would increasingly attract him over the remainder of his life, the string quartet, and composed a work that manages to combine playfulness with the most profound seriousness. That is a strange mix, and here it is a convincing one.

The structure of this quartet is unusual (five movements, with themes from earlier movements recalled in the finale), and the writing is quite demanding. Much of it is in the instruments’ higher registers, and there are moments of soloistic brilliance that seem at odds with the ensemble playing expected in quartets. In addition, the harmonic language can be gritty – each movement has a key signature and a home key, but a clear sense of tonality is obscured by the continuously chromatic writing.

All this makes the Third Quartet sound forbidding, which it is not. But it is quite varied music, and listeners should come to it ready for the broad range of expression that marks

Shostakovich’s best music. The very beginning of the opening Allegretto is frankly playful. The first violin’s skittering main idea dances gracefully, but Shostakovich stresses to all four players that he wants this beginning dolce. By contrast, the second theme is somber, pulsing darkly on its two-note cadence, and from the collision of these two ideas Shostakovich builds this sonata-form movement.

A pounding 3/4 pulse continues virtually throughout the Moderato con moto. There are moments when this meter verges on a ghostly, frozen waltz, only to be straitjacketed back into rigidity. The movement fades into silence with all the instruments muted.

By contrast, the Allegro non troppo explodes to life with what sound like gunshots. Built on alternating measures of 2/3 and 3/4, this scherzo – reminiscent of the “battle” movement of Shostakovich’s wartime Eighth Symphony – rushes to a sudden close.

The expressive Adagio has reminded many of Beethoven’s late quartets. It opens with a powerful five-measure phrase that will function (somewhat) like the repeating bass of a passacaglia, providing the foundation over which Shostakovich will spin out long spans of intense and moving melody. This proceeds without pause into the finale, which might have been a lighthearted conclusion, were the main idea not so spooky: The cello’s dark, sinuous main theme is accompanied by the viola’s pizzicato harmonics. As this movement dances along, Shostakovich gradually brings back themes from the earlier movements, and the quartet fades enigmatically into silence on a final chord marked morendo.

-- Writer and lecturer Eric Bromberger also contributes program notes to the Minnesota Orchestra, the Washington Performing Arts Society at the Kennedy Center, and the La Jolla Chamber Music Festival, among many others.