At its beginning, Anne Teresa De Keersmaeker’s Partita 2 asks both nothing and quite a lot of its audience. Both the stage and the audience are submerged in total darkness as violinist Amandine Beyer works her way through much of Bach’s Partita No. 2 in D Minor. The audience is left to contemplate a couple of things: when the dancers will appear, the richness of the music and Beyer’s performance of it. When De Keersmaeker and Boris Charmatz do finally appear, at least 20 minutes have passed in the dark. It is a startling change: a panel of light appears on the otherwise dimly-lit stage, and the two dancers engage in what looks like a ritual – or else only a marked version of something larger.

As the piece progresses, the two of them jog, gesture, jump, skip and fall off balance. Charmatz is a beautifully fluid mover with limbs that are both somehow gangly and gentle. It’s as if a gazelle has bounded onstage – in a way that still makes sense. In a particularly memorable sequence, one dancer lies on her or his shoulder as the other remains upright, walking carefully. The dancer on the ground matches her or his sideways steps to that of the upright dancer’s. Then, they clasp wrists and share weight until they have exchanged places.

Part of the piece’s strength lies in its repetitiveness. De Keersmaeker and Charmatz are wise to realize that a phrase repeated once, twice or even three times is not an uninteresting one. I think most audiences are often overwhelmed by the barrage of movement that occurs at many performances; the chance to become familiar with a work even as it is happening feels like a small gift. And the two dancers’ subtle changes to a phrase each time it was performed – while humming the score or as the score is played by Beyer, sometimes with more speed – layered it anew each time.

I think it can difficult to describe what makes a particular performer so radiant, so watchable, but at least for me, I know that much of De Keersmaeker’s power lies in her subtlety and nuance. Nothing is off-limits for her – the way she touches the edge of the proscenium arch’s jutting corner, or the way she gives each tiny gesture such clear investment and rigor. When she bows, she is unsmiling. (Whilst this doesn’t actually speak of her as a performer, it interests me.)

In a program note, De Keersmaeker speaks of the hesitation she felt to create a male-female duet, that it might make the performance seem forced. “I think we should be able to separate the bodies from each other,” she says. As ambitious as that sounds, I found myself approaching the piece from that very avenue of thought: what was before me wasn’t a story of romance or even any kind of relationship, really. (If forced, I would say De Keersmaeker and Charmatz’s interactions could best be described as sibling-like.) Often, it didn’t even feel like a duet. Or a trio. Instead, it felt pure. Simple. Depth-filled. In fact, it felt as perfect as dance can be.