The piece is unique among Mahler's symphonies in ending in an unambiguously tragic manner. All the other symphonies end happily or contenedly apart from the Symphony No. 9 which is often described as ending in a mood of quiet resignation. Many people have commented on this unexpectedness of the sixth's tragic tone given the fact that it was composed in what were, for Mahler, exceptioanlly happy times - he had married Alma Schindler in 1902, and during the course of the work's composition his first two daughters were born.
Bruno Walter claimed that Mahler himself gave the symphony its nickname The Tragic. While it is not absolutely clear that this is the case, it is true that Mahler knew of the name and did not initially object to it (although he did not include it in the first edition of the score).
Perhaps because of its grim mood, the symphony is not very popular amongst general listeners. However, it is reckoned by many to be one of Mahler's best, and both Alban Berg and Anton Webern praised it when they first heard it and the work is thought to be most highly regarded by musicians themselves.
The symphony is written for a large orchestra comprising four flutes, two piccolos, four oboes, cor anglais, clarinets, a bass clarinet, four bassoons, a double bassoon, eight French horns, six trumpets, three trombones, a bass trombone, a tuba, timpani, glockenspiel, cowbells, bells, Rute, hammer (see below), cymbals, side drum, xylophone, triangle, two harps, celesta and strings (violins, violas, cellos and double basses). Unlike several other Mahler symphonies, there are no vocal forces.
The sound of the "hammer" which features in the last movement was stipulated by Mahler to be "brief and mighty, but dull in resonance and with a non-metallic character". In modern performances, a wooden mallet striking a wooden surface is often used.
The work is in four movements:
Formally, the symphony is one of Mahler's most conventional, being one of only four to have the traditional number of four movements. The form and character of each individual movement is also quite traditional, with a fairly standard sonata form first movement (which even includes an exact repeat of the exposition, most unusual in Mahler), leading to the middle movements, one slow, the other a scherzo, and the finale, also in sonata form, quicker and recapping much of the previously heard material.
The first movement, which for the most part has the character of a march, is features a motif consisting of an A major triad turning to A minor over a distinctive timpani rhythm (the chords are played by trumpets and oboes when first heard):
This motif, which some commentators have linked with fate, reappears in subsequent movements. The first movement also features a soaring melody which the composer's wife, Alma Mahler, claimed was representative of her; this melody is now often known as the "Alma theme". The symphony ends in a happy mood with a restatement of the Alma theme.
The scherzo is in much the same unrelenting mood as the march sections of the first movement. Its trio (the middle section) is rhythmically irregular and marked Altvšterisch (old-fashioned). The slow movement is calmer, and the only movement not in A minor, instead starting in E flat major and ending in E major.
The last movement is punctuated by three hammer blows. Alma quotes her husband as saying that these were three mighty blows of fate befallen by the hero, "the third of which fells him like a tree". When he revised the work, Mahler removed the last of these blows (apparently for superstitious reasons), though most modern performances include it.
The piece ends with the same rhythmic motif that first appeared in the first movement, but the chord above it is a simple A minor triad, rather than A major turning into A minor.