“My Sixth will propound riddles.” Truer words were never spoken — and some of those riddles would surprise even the speaker, Gustav Mahler, were he still with us. Benjamin Zander’s performance with the Boston Philharmonic Youth Orchestra at Symphony Hall didn’t solve all of them, and one could quibble about his interpretation. But the kids were definitely all right.

The riddles start with how the Sixth got to be the “Tragic” symphony. Schubert subtitled his Fourth Symphony Tragische, and Brahms wrote a Tragische Overtüre. Neither  is remotely as tragic as Mahler’s. The nickname first turns up on the program for the Sixth’s Vienna premiere, which Mahler himself conducted, on January 4, 1907. Mahler’s friend and protégé Bruno Walter wrote that “Mahler called it his Tragic Symphony,” but there’s no direct evidence that Mahler did, and the name doesn’t appear on any of the published scores. Perhaps the Vienna concert’s producer thought Tragische would help sell tickets. Mahler might have been enthusiastic; he might agreed with reluctance; he might not have been consulted. We just don’t know.

We’re similarly in the dark about why Mahler borrowed a theme from Franz Liszt’s First Piano Concerto. At bar 35 of the Allegro energico, the trombones quote a seven-note motif from bar 17 of the concerto’s third movement. It’s not a passing fancy — when the horns blast it out in the coda (bar 466), you know the theme is a major player. What was Mahler thinking? He had conducted the concerto in 1903; perhaps it stuck in his mind. What’s really strange, though, is that on November 8, 1906, both the Liszt concerto and the Mahler symphony appeared on the same program in Munich. (The symphony came first, the concerto after intermission — imagine such an arrangement today!) Did any of the concert’s reviewers notice?

Some other riddles are relatively trivial. According to Mahler’s wife, Alma, the soaring F-major second theme in the Allegro energico was his attempt to depict her in music. We don’t have that from Mahler himself; assuming he did say it, it’s conceivable he was hoping to placate her after working too long in the composing hut one afternoon and arriving home late for dinner. Then again, if the Sixth is in any way autobiographical (and what Mahler symphony isn’t?), Alma should be in it.

Alma also tells us, “In the third movement he represented the unrhythmic games of the two little children, tottering in zigzags over the sand.” This can’t be quite right: of Mahler’s two daughters, Maria Anna was born in November 1902 and Anna Justine in July 1904. Mahler sketched out the Scherzo (that’s the movement Alma meant) in the summer of 1903, so one child can hardly be tottering around, let alone two. All the same, it’s an apt description of the Scherzo’s “Alväterisch” (“old-fashioned”) Trio.

The remaining riddles — the order of the inner movements, and the matter of the third hammer blow in the finale — are more vexing. We know from his sketches that Mahler was conflicted over whether the Scherzo should precede the Andante or vice versa. By the time he arrived in Essen for the symphony’s premiere, in May 1906, C.F. Kahnt had printed a study score with the Scherzo coming first. Mahler agonized through rehearsals before deciding to conduct the premiere with the Andante preceding the Scherzo. He then instructed Kahnt to print a new edition with that order, and to insert errata slips in the already printed Scherzo-Andante copies. He never conducted, or heard, the symphony any other way.

Most of us, however, grew up with the Scherzo preceding the Andante. That’s because it’s the order ordained by the Critical Edition published by the Internationale Gustav Mahler Gesellschaft in 1963. The editor, Erwin Ratz, explained that, before his death, Mahler had realized his mistake and reverted to the Scherzo-Andante order. Conductors took Ratz at his word — but he had no evidence other than a telegram from Alma that may have represented her own opinion, or a dodgy memory. (Recall that, in her account of the children’s zigzag tottering, she identified the Scherzo as the third movement, not the second.) If Mahler had had second thoughts about movement order, he would surely have communicated them to colleagues like Bruno Walter and William Mengelberg, not to mention his publisher.

It’s clear what Mahler’s final decision was, but we can also see why he was conflicted. His Sixth begins in A minor; surely it aspires to a major key. But which one? The Allegro energico concludes in a blazing A major; what does that leave for the Finale? The “Garden” section of the Allegro energico is in E-flat, and so is the Andante. The finale begins in C minor (the relative minor of E-flat), and in the course of 30-plus minutes it strives for both A major and E-flat. Scherzo-Andante leads toward A major, Andante-Scherzo toward E-flat. No wonder conductors are conflicted.

As for the hammer blows, Alma tells us that Mahler described them as “ ‘the three blows of fate, the last of which fells him [the symphony’s hero] as a tree is felled.’ Those were his words.” She would have it that her husband deleted the third one, in the summer of 1906, after the Essen premiere, because he was superstitious. But Mahler’s autograph shows that there were originally five hammer blows, at bars 9, 336, 479, 530, and 783. So much for the magic number of three. The first, fourth, and fifth are parallel; they support the “fate” rhythm and major-to-minor triad near the beginning of the introduction, the recapitulation, and the coda. You’d expect to hear all three or none. The original second and third blows mark the collapse of optimistic sequences in the development. Before the Essen premiere, Mahler deleted the hammer blows at bars 9 and 530; the mystery is why he waited till the summer of 1906 to delete the one at bar 783. In any event, the Sixth was conceived with five hammer blows, it had three for only a few months, then wound up with two. Was Mahler really superstitious?

Zander has recorded the Sixth three times: with the BPO in the mid 1980s (BPO home label) and again in 1994 (IMP), and with the Philharmonia of London in 2001 (Telarc). All three recordings include the third hammer blow, with Zander arguing that “Fate cannot any longer be felt to stand threateningly over the composer.” The first BPO release (on audiotape only) has the Andante preceding the Scherzo, though Zander’s liner note suggested he wasn’t entirely comfortable with performing the symphony that way. The two later recordings have the Scherzo before the Andante, Zander explaining that he was following “Mahler the composer” rather than “Mahler the conductor.”

In practice, that last hammer blow at bar 783 shouldn’t matter: the finale has already crashed at bar 773, the melody descending to what it hoped was an A-major chord only to find a naked A waiting. And if a conductor can’t feel right about Andante-Scherzo, it makes sense to stick with the more familiar Scherzo-Andante — which Mahler didn’t discard lightly, and which conductors ranging from Jascha Horenstein and Rafael Kubelik to Klaus Tennstedt and Leonard Bernstein have made to work over the past 50+ years. I do wish Zander would seat his first and second violins antiphonally, since that’s the arrangement Mahler wrote for, but he’s hardly the only conductor who doesn’t.

A week ago Friday, Symphony Hall was packed for Zander’s performance of Mahler’s Second Symphony with the Boston Philharmonic Orchestra. Sunday’s audience was palpably smaller. The Sixth is certainly less uplifting than the Resurrection, but did potential patrons also suspect the BPYO wouldn’t be up to the symphony’s ferocious demands? I heard no evidence to support such doubts. Zander assembled a huge orchestra, 79 strings, 131 instruments in all. If there was the odd bobble in the brass, well, there were a few in the BSO’s Bruckner Sixth earlier this month. The celesta sounded oddly recessed in the first movement but was fine in the finale. The xylophone, a kind of dancing skeleton, was as prominent as it needs to be; the English horn in the Andante was particularly heartwrenching. As I left Symphony Hall, I heard a veteran usher say, to no one in particular, “Those kids are so talented,” almost as if he were expecting an argument. He got none from me.

Zander’s interpretation did not wrench hearts as it might have. It stuck pretty close, if memory serves, to the one he gave with the Philharmonic in February 2013 in Jordan Hall. At 80 minutes, it was about six minutes faster than the 2001 Philharmonia recording. The movement timings were almost identical to the ones Mahler penciled in on the score he brought to the Essen premiere: 23, 12 (Scherzo), 15 (Andante), and 30. It may seem presumptuous to criticize a conductor for doing what the composer has asked him to, but as with Zander’s Bruckner Ninth with the Philharmonic back in February, this Sixth could have had more air, more pointed paragraphing, a greater sense of ebb and flow. It boasted the kind of modernist, straightforward outline you’d expect from a Christoph von Dohnányi or a Michael Gielen. Which is to say, on its own terms, it worked.

The Allegro energico certainly found the right contrast between the initial syncopated death march and the “Alma” second theme. The one was relentless; the other, holding back, seemed to say that love can stop time. Later on in the movement, there’s a point where love actually does: a “Garden” idyll with celesta and cowbells that eventually settles into E-flat major. T.S. Eliot’s “moment out of time,” it has to stand outside the rest of the Allegro energico; here it was too much inside. Overall, the movement had a burnished splendor that reflected the majesty of death; credit Zander for not going so fast as to tarnish that, and the orchestra for executing. But in keeping with the general restraint, Mahler’s “molto rit.” at the climax (bar 473), as the “Alma” theme emerges victorious, was understated to a fault.

Every Mahler symphony tells a story; in the version of the Sixth where the Scherzo precedes the Andante, death returns in A minor to refute the Allegro energico’s apparent A-major triumph. Zander began this distorted Ländler as ferociously as one could want, but at a tempo that suggested the Allegro energico was beginning all over again. (This problem may well have been what bothered Mahler at Essen, and what prompted him to have the Andante precede the Scherzo.) The “Altväterisch” Trio creaks as it stumbles from 4/8 to 3/8 to 3/4; Mahler marks it “merklich langsamer” (“perceptibly slower”), but here the slowing was barely perceptible, and the same was true of the spooky F-minor section that follows.

Zander conducts BPYO in Mahler 6 (Stu Rosner photo)
The Andante attempts to circumvent the A-minor/major struggle by returning to E-flat. It begins with a consoling lullaby, but as early as bar 9 it’s alluding to the first of Mahler’s Kindertotenlieder, “Nun will die Sonn’ so hell aufgeh’n,” suggesting that in the Scherzo death has claimed one or more children. Zander didn’t create much contrast between the lullaby and the anguished, passionate second theme, which seems to lament that loss.

Mahler’s Finale is extraordinarily difficult just to analyze, never mind conduct. Zander held it together, which is no small feat. What I missed was the tension and release of the more sprawling readings from Horenstein, Bernstein, Barbirolli, Tennstedt, even former BSO percussionist Harold Farberman. The Finale is a kind of supernova, spewing out matter before the inevitable collapse; it’s as glorious, especially in its wild A-major ride, as it is tragic, and Zander did convey that.

He also changed my mind about the third hammer blow. His Finale didn’t crash at bar 773; there was relatively little agony when A major failed to materialize there, still hope that the fate motif in the harp would lead to A major in bar 783. Instead, the third hammer blow dispelled all doubt. All three hammer blows had, as in previous Zander performances of the Sixth, the dull, ax-like sound Mahler wanted and had difficulty getting in his own performances. I think the composer would have been pleased.

Over some 40 years, Zander has programmed the Sixth, with the Philarmonic and with NEC orchestras, more times than I can remember; it and the Ninth seem to be his favorites of the master, or at least the ones he does battle with most often. Without him, Boston would have heard the Sixth live only in the odd BSO performance from Erich Leinsdorf, Seiji Ozawa, or James Levine. The Sixth is one of the greatest symphonies ever written; let us give thanks for Zander’s advocacy.

Click here to listen to the recording.