Ms. Dinnerstein, 45, wanted to work with a choreographer in order to stretch her own artistry. Ms. Tanowitz has stretched hers without realizing that she would: “I took the gig for one reason, but I’m actually ending up in a different place,” she said.

As usual, intricate steps are bountiful in her choreography for “New Work.” But there is also space and air between them. “This piece has been an exercise in restraint,” she continued. “I’m allowing myself to do things that I haven’t done in the past: to let certain things flow.”

Ms. Tanowitz’s dances brim with inventive footwork and rigorous, often stringent choreography, in which the influence of Merce Cunningham is often apparent, yet the Bach has unleashed a more humane lushness in her approach.

Growing up in New Rochelle, N.Y., Ms. Tanowitz studied modern dance at the Steffi Nossen School of Dance. She was never a member of a major dance company, but when she attended graduate school at Sarah Lawrence College, she met Viola Farber, the former Merce Cunningham dancer, who became a mentor.

“She loved dancing, just dancing,” Ms. Tanowitz said, “And she gave me that love of dancing back.”

Ms. Tanowitz is passionate about dance history, like her mentor was; she frequently includes references to works by an older generation in both ballet and the modern vernacular. That’s another reason she was intimidated by Bach. His music has been used by many choreographers over the years, but most nail-bitingly for her, by Jerome Robbins, whose celebrated “The Goldberg Variations” was made for New York City Ballet in 1971.