Mahan Esfahani, an approachable wizard of the harpsichord, conveyed with immediacy why he had become spellbound by the instrument. His playing and communication—alone and with the Escher (String) Quartet—for the Rockport Chamber Music on Sunday were nothing short of stunning.

Escher Quartet, founded in 2005, with original members Adam Barnett-Hart (violin 1), Pierre Lapointe (viola), and later additions Brendan Speltz (violin 2), and Brook Speltz (cello), added focus, verve, concentration and, it seemed, piquancy and humor. The unusual choices of repertoire, particularly the world premiere of Composer-in-Residence Mark Applebaum’s October 1582, for solo harpsichord, and a few other surprises, made for a remarkable concert.

Esfahani rendered Bach’s, Concerto in the Italian Style, in F Major, BWV 971, with intensity and intentional phrasing via short pauses, reminding us that this work is FOR the harpsichord (though I am so used to hearing it on a modern piano that the original version, heard here, seemed a bit subdued). Published in 1735, this keyboard “concerto” is Bach’s only example for a single harpsichord. The soloist’s soft effectiveness made the piece seem all the more unique.

The Escher then performed four fugues (of the 5 from K405) which Mozart arranged from Bach’s Well-Tempered Clavier, Book 2—BWV 871 (C minor) and then 876 (E-flat major) ,7 (D-sharp minor) and 8 (E major), with which Mozart had charmed his then fiancée, Constanze. The voices of a string quartet certainly expand upon the unspecified clavier, adding varieties of shades, timbres, and nuance.

Bach’s A Major Concerto for Harpsichord, Strings and Continuo (1738), which reflects the composer’s mature sensibilities, worked well with the cellist of a quartet playing the continuo part and the other three melodically supporting the harpsichord. Likely originally written for oboe, strings and continuo, in this later version, a harpsichord can seem overwhelmed. But here the keyboard held its own with the robust sounds of the four strings, perhaps helped by the acoustics of the Shalin Liu. While the work is often played with additional string players, including double bass, that constellation balances better with a modern piano.

After the intermission Esfahani summoned Mark Applebaum to the stage before the premiere to talk about his October, 1582, named after the year in which ten days de-materialized, as the Julian Calendar transitioned to the Gregorian. The work pays homage to those unknown days—and more. The composer noted that each interlude is short, “so you don’t have to wait long until the next one, if you find the movement annoying, even though you might not like that next one, either.” All have sentient and catchy names such as, “October 5^th, Falling Grace,” which emphasizes the two keyboards of the instrument and drops to some bells kept on the performer’s lap. The work is distinctly for harpsichord, commissioned for Esfahani, whose collaborations with the composer go back to his student days at Stanford in Applebaum’s course. The names of the other sections are worth just noting— “October 6, Cannon Fire,” with 27 second, 18 second and 9 second segments, ending with, a fusillade of notes yet a nod to the canon; “October 7^th, Omnibus in the key of W,” an electronic intervention; “October 8^th, Sky,” with jazzy chords and reverberations; “October 9^th, WTC,” referring to the Well-Tempered Clavier and another WTC we all know too well; “October 10^th, Roof Skeletons,” a nod to Sir Thomas Beecham’s opinion [copulating skeletons on a tin roof] of harpsichords, which uses chopsticks; “October 11^th, Dodecahedron,” essentially dedicated to Esfahani, including a 12-note pattern, circle of fifths, and fourths removed, ending tonally; “October 12^th, Packing List,” which features speaking and varied sequence and words at each performance; “October 13^th, Khodabanda,” a kind and learned 16^th-century Persian shah, and a reference to the performer; and finally, “October 14^th, Turn, Turn, Turn,” which is silent. My hope is that those reading here will be sufficiently intrigued to be sure to hear this gem, which I warrant will endure as an audience fave and staple.

The final concert segment hailed from the Art of Fugue (BWV 1080) written in Eisenach, Germany, at the very end of Bach’s life. Here the arrangement for string quartet and harpsichord ended with a fade out, as Bach left it uncompleted.

Many from the excited audience stayed for a Q and A in which questions about the harpsichord, its role over time and its future could have kept all from dinner, as there was such interest, if Artistic Director Barry Shiffman had not finally said, “last question.”

Mahan Esfahani and the Escher String Quartet, together with innovators such as Mark Applebaum, are ensuring the harpsichord’s continuing relevance.

Julie Ingelfinger studied piano at the Hartt School of Music, Aspen Music Festival and School and at Harvard. She enjoys her day jobs as professor of pediatrics at Harvard Medical School, pediatric nephrologist at Mass General Hospital for Children and deputy editor at the New England Journal of Medicine.