The jazz pianist Dan Tepfer first heard Bach’s Goldberg Variations (BWV 988) when he was a teenager and a friend played him a recording. He was instantly awe-struck by the music. He also recognized in Bach a fellow spirit, a fellow improviser.

Mr. Tepfer, 31, a busy jazz artist who has performed and recorded with giants like the saxophonist Lee Konitz, told this story to an audience at Le Poisson Rouge, the Greenwich Village club, on Thursday night, 12 September 2013. He then performed his signature version of Bach’s monumental work, Goldberg Variations/Variations by Bach/Tepfer. He recorded it in 2011 on Sunnyside Records.

Bach’s keyboard masterpiece is written in the form of an alluring aria with thirty variations. In Mr. Tepfer’s riveting and inspired version, after performing each Bach variation, he follows up with his own improvised one that becomes a musical commentary and takeoff on the Bach. “It’s always an adventure,” Mr. Tepfer told the audience.

Adventure was the right word for the brilliant performance he gave. Naturally, each time he plays his improvised takes on Bach’s variations, the music turns out differently. He has a basic concept of each one in mind, he said during a brief interview after the concert. But the resulting notes are different, sometimes very different, especially in the slow variations, when “I have more time to think,” he said.

As he also explained to the audience before playing, Bach’s work is a set of variations not on a melody, but on a bass line and series of chords (a harmonic pattern). This is close to what jazz musicians do when they play improvisations on a standard, Mr. Tepfer said. They improvise variations over the “changes,” that is, the chord patterns of the theme.

I was engrossed from the start of the ninety-minute performance, when he played Bach’s aria with such sensitivity and grace, then brought articulate touch and naturalness to Bach’s jaunty first variation. His improvisation on that variation picked up on the dancing gait of the Bach but made it more jerky and unpredictable. He let his imagination go with strands of syncopated passagework and clashing harmonies. The playful walking bass figure in Bach’s second variation became a galumphing bass line in Mr. Tepfer’s improvisation, with a sassy, biting right hand.

Mr. Tepfer’s variations were often bold adventures in modern jazz. Bach’s ninth variation, written as a canon at the third (a contrapuntal technique), became an exercise in soft thick chords with wrong-note contrapuntal inner voices. Bach’s fourteenth variation, a burst of virtuosity that builds to passages where the right and left hands have feisty showdowns of racing turns and spiraling runs, became a gnarly, gnashing and relentless improvisation in Mr. Tepfer’s conception: imagine Bartók as a jazz pianist. The mournful Variation no. 25, which Mr. Tepfer played poignantly, was in his reimagining a soulful rumination: a searching melodic line tries to break free from hushed, piercing cluster chords.

This is no stunt, but a fresh musical exploration. Mr. Tepfer invites you to hear this masterpiece through his ears. I bet Bach would recognize a kindred spirit in Mr. Tepfer.

Anthony Tommasini – The New York Times