Fresh off yet more Grammy Awards for their ongoing Shostakovich cycle (no complaints from this corner), Andris Nelsons and the Boston Symphony Orchestra celebrated Valentine’s Day with a pair of love letters. Schumann’s Piano Concerto in A Minor was, like virtually everything he composed for the piano, written for his pianist wife, Clara — he even spells out her name in the theme of the opening Allegro affettuoso. And Bruckner’s unfinished final symphony, the Ninth, is dedicated to his “beloved God.” It’s not the first time this pair have been presented in Symphony Hall — back in October of 1999, the Celebrity Series treated us to Claudio Abbado and the Berlin Philharmonic, with Maurizio Pollini as the piano soloist. Thursday’s presentation of the concerto, with Yuja Wang as the soloist, was quite different but no less affecting. The symphony, however, posed a bit of a puzzle.

Schumann’s piano concerto — he wrote just the one — started life in 1841 as a single-movement Phantasie in A Minor for piano and orchestra. Premiered in Leipzig with Clara as soloist, it did not meet with success. At Clara’s urging, Robert eventually expanded the piece into a three-movement concerto that premiered in Dresden in 1845, again with Clara as soloist. Since then it’s become one of the most popular piano concertos in the repertoire.

Right from the start, Schumann behaves like, well, Schumann. After an initial eighth-note E in the orchestra, the piano breaks in with a cascade of descending figures that suggest the composer’s impulsive, impetuous alter ego, Florestan. The oboe then introduces Schumann’s other alter ego, poetic, dreamy Eusebius, by way of a wistful melody that, in a normal concerto, would be the second, subsidiary theme. Here it’s the centerpiece of the movement. The first four notes are C-B-A-A; in German notation, that’s C-H-A-A — or, filling in the blanks, CHiArA, the Italian form of Clara. Recollect that the “Chiarina” waltz of Carnaval represented Clara and the meaning here is unmistakable. (The major-key form of this motif is identical to the beginning of Senta’s redemption theme in Der fliegende Holländer. There’s no question of borrowing here, however: the motif was central to the 1841 Phantasie version of the concerto’s first movement, and I don’t imagine Wagner had heard Clara play that piece by the time his opera premiered in Dresden in 1843.)

Schumann goes on in this Allegro affettuoso first movement to introduce secondary themes that sound more like energetic first themes, and to subvert sonata form while appearing to observe it. The movement is really about Eusebius and Florestan, and yet interpretations tend to minimize the contrast. Perhaps the “affettuoso” marking — suggesting tenderness and affection — has misled pianists into thinking there’s no drama here. After all, it’s 1845, and Clara has long since been won. What is there to replace the anguish and the yearning of Carnaval and Kreisleriana and Davidsbündlertänze and the great Fantasie in C? Well, Eusebius and Florestan continue to have it out, and that’s fertile ground for any imaginative pianist.

Wang belongs to that elite group. She’s relatively new to the concerto, so her interpretation is still taking shape. Last month, in a performance with Lionel Bringuier and the Staatskapelle Dresden, Florestan seemed to look about for a split second before jumping in. Thursday at Symphony Hall, he bolted from the gate. Interpretive nuances aside, Wang understands that this is a Romantic piano concerto. Her Eusebius, as represented by the CHiArA theme, felt spontaneous and personal, and in the first movement with Nelsons directed a conversation in which Eusebius and Florestan would, from time to time, exchange masks.

The orchestra, at an appropriate size, just some 40 strings (the Bruckner would have close to 60), allowed winds and trumpets and French horns to project well. Warm and intimate to begin with, Nelsons eventually grew militant and heroic in the secondary themes, as if Schumann were strutting about. The solo-piano beginning of the development, which Schumann marks “Andante espressivo,” was all moonlight, and Wang’s playing in the first half of the cadenza recalled the passionate first movement of the Fantasie. The coda, where the time signature shifts from 4/4 to 2/4, became a children’s march, or perhaps Schumann’s Davidsbund marching against the musical Philistines. Toward the end Nelsons made it sound almost spooky.

Schumann titled the 2/4 second movement Intermezzo: Andantino grazioso and supplied a metronome mark of 120 eighth notes to the minute. Since the movement comprises just 108 measures, that works out to a timing of just under four minutes. The only pianists I know who’ve done it in less than five are Guiomar Novaes (4:22!), Andreas Staier (on an 1850 pianoforte), and Angela Hewitt — but the point is that Schumann really meant this to be an intermezzo and not a slow-movement romance. The piano starts up with a rising four-note figure and the orchestra follows; it’s Clara and Robert playing musical tag in a teasing movement that harks back to Kinderszenen and looks ahead to the Album für die Jugend.

Wang took those first four notes with supreme lightness, and Nelsons answered as if finishing her sentence. The movement ran about five minutes, but it had the long arc that I think Schumann envisioned. The middle section finds the cellos sighing and the piano responding with amusement. Here Nelsons seemed to be Romantic Robert and Wang a more practical Clara with a household to run and (by this time) three children to look after, not to mention her career as a concert pianist.

The Allegro vivace finale, in 3/4, is a romp that occasionally marches and toward the end wants to waltz. Apart from the transition from the Intermezzo, which reintroduces the CHiArA theme, I’ve always found it the least distinctive movement of the concerto, and that was true Thursday. In his 1953 Deutsche Grammophone recording with Rafael Kubelik and the Berlin Philharmonic, Géza Anda plays the cyclic digressions with what sounds like no pedal; the effect is as effervescent as champagne bubbles. Wang’s pearly fingerwork in these passages was spirited but more conventional. Also conventional was the 10-minute time span. The movement runs 881 measures, which at Schumann’s metronome mark of 72 dotted half-notes per minute works out to more than 12 minutes. One can always question Schumann’s metronome markings, but here the more relaxed feel of Anda’s 10:55 and Hewitt’s 11:38 might be closer to what he had in mind.

In her encore, Giovanni Sgambati’s arrangement of the Dance of the Blessed Spirits from Gluck’s Orfeo ed Euridice, as in the concerto, we found her rhapsodic but never self-indulgent.

Nelsons is actually under Deutsche Grammophon contract to record two symphonic cycles: Shostakovich with the BSO and Bruckner with his other orchestra, the Leipzig Gewandhaus. So far it’s the BSO Shostakovich discs that have garnered all the Grammys, but the Leipzig Bruckner releases (Nos. 3, 4, and 7 so far) have been creditable, and the contract means more Bruckner in Symphony Hall — a consummation devoutly to be wished. Nelsons’s predecessors — from Koussevitzky and Munch on through Leinsdorf, Steinberg, Ozawa, and Levine — have not been big Bruckner proponents, though RCA did release a fine BSO/Steinberg performance of the Sixth from 1970.

Bruckner’s Ninth is as cosmic as the Schumann concerto is personal. Had he finished the fourth and final movement, it would have run close to an hour and a half. Like Beethoven’s Ninth, the symphony begins in D minor, and like that Ninth, it opens on a string tremolo, the oscillation of the quantum universe. The first subject group alone has eight elements (as Derek Watson pointed out, “There are more things of heaven and earth than were ever dreamt of in any other first-subject group”), climaxing with three tremendous octave crashes into the Pit, the last of which drops from E-flat to a momentary D before recovering to E-flat. Rescue arrives via the lulling cradle song of the A-major second subject, but the underpinning seven-note ostinato in the second violins betrays the composer’s counting mania. The third subject, back in D minor, finds the first violins obsessing over D while an ominous descending ostinato develops in the clarinets and troubling harmonic vistas unfold.

Bruckner eschews development in favor of counterstatements where the original themes appear in new and increasingly alarming colors; it’s as if our mission were, in T.S. Eliot’s words, “to arrive where we started/And know the place for the first time.” The cacophonous climax finds the first violins clinging to a stratospheric B-flat while the French horns and violas get claustrophobic. The coda begins with a menacing drumroll and a mist of anarchic mutterings that clear to reveal Bruckner’s dark angels processing through the thorn trees. Last Judgment hysteria mounts in the string ostinatos while the trumpets obsess on E, and when the orchestra subsides into a mock-triumphant D minor, the trumpets try to lift the movement into E-flat, their outbursts heroically, horrifically, failing as the orchestra drags them down. They might as well be Marlowe’s Faust, or Mozart’s Don Giovanni.

The jackhammer Scherzo — also in D minor, but the second violins lead another nasty, dissonant revolt with their insistent D-flat — is “relieved” by an F-sharp Trio that slithers about the Garden with its apple. The E-major Adagio, straight out of Caspar David Friedrich’s Arctic Shipwreck, opens on an upward-leaping ninth that withholds the security of a home key. Religious consolation is attempted by a second subject in A-flat (the home key of Parsifal), but the movement persists in its lonely pilgrimage through icy wastes to an illusory oasis that looks ahead to The Ten Commandments (you can practically hear Cecil B. DeMille intoning, “And Moses dwelt among the shepherds of Midian . . . ”) and then a chromatic nightmare (seven of the 12 notes of that scale fused in a single death’s-head chord). It all limps home to a humpback-whale-soothing E major via allusions to the Miserere of Bruckner’s D-minor Mass, the Adagio of his Eighth, and the opening phrase of his Seventh. The finale, to judge from the fragments he left, would have been apocalyptic.

The Bruckner Fourth that I heard from Nelsons and the BSO in November of 2017 blazed and flickered, ebbed and flowed, everything in place and with ample air around the discrete sections. At 68 minutes, it had room to expand and explore. This Ninth seemed compressed and congested. It was relatively quick: 24 minutes for the opening “Feierlich, Misterioso,” 10 for the Scherzo, 22:30 for the Adagio. Yet conductors as disparate as Karajan and Furtwängler have gone faster and made more apparent sense. It was the logic of Nelsons’s reading that eluded me.

The opening French-horn call slid by without apprehension, and there was no awe in the build-up to the octave crashes. The “Feierlich” marking indicates “Solemn,” but Nelsons drove forward as if he were challenging the heavens rather than exploring them. The second subject is marked “Langsamer” (“Slower”); here he actually picked up the pace. And the “Misterioso” third subject was anything but. Where Bruckner creates blocks of subject matter each with its own tempo, Nelsons let one bleed into the next. Tempos merged, shape wasn’t apparent, the big climax was noisy rather than dissonant, and the coda, perhaps the most frightening thing Bruckner ever wrote, just rolled along.

Nelsons’s Scherzo was good enough, even with a less than seductive Trio. His Adagio was not. The movement is subtitled “Langsam, feierlich,” and here Bruckner becomes more chromatic than ever, the harmonies stranded in space, looking everywhere for their Creator. The conductor is invited to join the composer in wondering where all this is going. That can reasonably take some 26 minutes. Nelsons, without wonder, seemed to know where he was going, and maybe he did. I just wasn’t able to follow him.

Nelsons and the BSO will repeat this program Friday February 15 at 1:30 p.m. and Saturday February 16 at 8 p.m.

Jeffrey Gantz has been writing about music, dance, theater, art, film, and books for the past 35 years, first for the Boston Phoenix and currently for the Boston Globe.