Robert Levin, the formidable fortepianist, historian, lecturer and intellect, joined the Handel & Haydn Society’s period band for a spirited and probing performance of Beethoven’s Piano Concerto No. 4 in G-major, Op. 58 Friday evening, October 29, in Symphony Hall. The performance is repeated tomorrow — Sunday. Bernard Labadie, the French-Canadian leader of the Quebec-based Les Violons du Roy and La Chapelle de Quebec early music ensembles presided as accompanist and equal partner in exploring this, Beethoven’s most personal, forward-looking and intellectually involving of his five concertos for piano.

Levin is not a shy soloist by any definition, and for that his audiences are truly grateful. In his commentary before the concerto performance, he gave a brief talk from the piano bench about the unique keyboard instrument he was about to play. And quite the instrument it is. Built in a Prague workshop and now owned by Harvard University, it is a contemporary copy of fortepianos which Beethoven most likely would have recognized. Indeed, its tone is highly reminiscent of a Broadwood of Beethoven’s time. But what makes this instrument unique, said Levin, is its singular ability to play the Fourth Concerto’s second movement precisely as Beethoven asks: “una corda.” Twentieth-century  pianos have a “soft pedal” that moves the instrument’s hammers slightly off-center, allowing the instrument to play on two of its normal three strings. Yet the resulting sound is a mere approximation of a true una corda sound, which, as literally translated, is the sound of “one string.” Levin’s instrument, he averred, is the only fortepiano he has played that actually allows only one string to be struck when una corda is applied. And it’s true – the resulting sound is otherworldly, almost “lunar,” as Levin characterized it later in his post-concert Q&A session.

What followed was certainly the fastest performance of this concerto that I have ever heard. There was nothing Moderato at all about the opening Allegro, and while the quick tempo afforded ample room for Levin to astonish with his uncannily fleet and accurate finger work, a certain sense of mystery and the sense of a wondrous tale unfolding were sacrificed. But there were compensations: right from the concerto’s first note, something new had been added. I was intrigued that Levin chose to arpeggiate the first chord. The reason for this was to be justified a bit later, but I cite it here as only one example of the many felicities Levin and Labadie gave to their exposition of this remarkable  music.

When Robert Levin plays a Mozart or Beethoven concerto these days, it is a given that he will improvise his cadenzas on the spot, as was the custom in Mozart or Beethoven’s day. This is no small task. A successful and stylistically appropriate improvisation requires a thorough knowledge of period style, plus the technical and intellectual gifts to bring it off effectively and dramatically. That Levin has become a master of this is well known, and his cadenzas are highly anticipated moments of his concerto performances. He did not disappoint in any of the four he played on Friday. In fact, he astonished. Skillfully weaving snippets of music heard before in the concerto and on-the-spot newly composed far-reaching excursions of his own, Levin made his way through each cadenza with a remarkable combination of virtuosity and taste. It was entertainment of the highest order, and greatly appreciated by those both off and on the stage, if the involved gazes and smiles from the H&H orchestra were any indication. A brief pause ensued at the end of the first movement, as Levin took a few minutes to disassemble his instrument to temporarily free a recalcitrant sticking hammer, after which the good-natured audience applauded his ministrations.

What all in the hall were awaiting, however, was the Concerto’s second movement, where the orchestra’s strings are tasked by Beethoven to play in unison and octaves as forcefully as possible in dialogue with the piano, which is asked to play as softly as possible. It was here that Levin’s fortepiano’s una corda was truly revelatory. I’ve never heard the resulting dynamic contrast so extraordinarily achieved – a tribute to Beethoven’s genius, certainly, but achievable only with this particular instrument’s capacity to play as the composer had directed. And, there was even something more. Once again, Levin arpeggiated several of his instrument’s initial pianissimo chords. An “a-ha moment” occurred as I wrote in my notes:  “…amazing una corda sound – huge contrast with orch. strings – arpeggiates lots of chords – perhaps mindful of Orpheus’s lute?” And so was explained the Concerto’s first arpeggiated chord. Even then, Levin was setting up the idea of the second movement’s long-assumed representation of Orpheus taming the Furies with his sweet sounding and softly stroked lute as he seeks his beloved Eurydice at the gates of the Underworld. In his post-concert talk, Levin averred that this indeed was what he had intended with his many arpeggiations. Even more wonders ensued in this remarkable movement. Near its end Beethoven writes a long trill for the keyboard over which is applied a long crescendo and diminuendo. Hearing Levin begin this trill with the fortepiano’s una corda applied, then abetting the volume of his crescendo by slowly moving from una corda to tres corda, then back again in making his diminuendo, was yet another demonstration of the power of Levin’s creativity as a gifted and informed musician.

The Rondo-Vivace that followed was just that, Vivace once again emphasized. A couple of what sounded like momentarily slipped notes were explained by Levin in his post-concert talk. Apparently the sticking hammer problem had returned, presenting even more vexing challenges than it had posed in the first movement.  I also had worried that Labadie’s bright tempo might compromise the even more quickened pace indicated at the Coda, but I needn’t have fretted – Levin and company dispatched this opportunity effortlessly. So all in all, a bracing, fleet, informed, and salutary performance of this nonpareil concerto by all concerned was heard and heartily applauded by all in the hall, on-stage orchestra and conductor as well.

There was Haydn to be heard this evening, too, and considerably wonderful it was. Labadie and the H&H orchestra played two symphonies that once again reaffirmed the great genius and boundless creativity of this remarkable composer. Though I would have preferred a couple more violas and ‘cellos to boost their overall balance with the violins, I was again struck by Haydn’s daring harmonic excursions and his wonderful sense of humor. This virtuoso group under Labadie’s energetic and demonstrative conducting thankfully played all to the hilt. The entire orchestra was spot-on; the wide dynamic range they exhibited throughout the evening was a joy to hear. The sensitive and musical contributions of Christopher Krueger, flute, Stephen Hammer, oboe, and John Grimes, tympani were especially noteworthy.

The key-of-G-centric program opened with the Symphony No. 83 in G-minor, “The Hen.” The avian association was amusingly heard in the first movement’s second subject, but it was the second movement in which Haydn’s creativity once again astonished. A series of six eighth notes begins the movement and becomes its cause celebre a bit later, when no fewer than twenty-two of these eighth notes are repeated by the strings piano diminuendo as preparation for an unanticipated fortissimo outburst from the orchestra. Talk about “surprises”! Despite a brief repeated error by the first violins in the Allegro spiritoso part of the first movement, Labadie and his willing collaborators made the most of this symphony, especially in its gigue-like spirited final movement. They did the same in the symphony, which closed the concert, the famous No. 94 in G-major, Surprise, or as German-speaking countries have it: “mit dem Paukenschlag” (with the tympani strike). As had become customary for the evening, Labadie led a brisk and dynamically nuanced performance with energy, wit and clarity. For me, the real “surprise” of this symphony’s second movement is not its celebrated and startling tympani-spiked fortissimo chord heard early on, but rather its daring harmonic excursions as its theme-and-variations format wends its way from one amazing measure to the next.

This was wonderful evening for H&H in Symphony Hall, I thought: robust and elegantly played Haydn, thoughtful, probing, and enlightening Beethoven with Robert Levin’s magisterial contributions, all stitched together by an energetic and inspiring conductor and the considerable combined talents of the orchestra members. Bravo to all concerned!

Note: This concert repeats on Sunday, October 31 at 3:00 PM.

John W. Ehrlich is music director of Spectrum Singers, which he founded 29 years ago. He has been a singer and conductor in the Boston area for more than 30 years.