LIU WENTAO’S PAINTING may be consistently monochrome, but it’s anything but monotonous. For nearly a decade, the artist has resisted using color in his work, obsessively reusing two materials—graphite and canvas—over and over again. Like the three preceding it, his fourth solo exhibition is held at the appropriately titled White Space (its Chinese name, “空白空间,” literally means “empty white space”) in Beijing’s Caochangdi. This emptiness is evident in the show’s title as well: xuan, generally translated as “black,” is left in the original Chinese. This decision is likely a semantic one: hei (黑), rather than xuan (玄), is used for the color in everyday speech, while xuan can also mean “profound” or “abstruse.” Liu’s works are all untitled, and their inscrutability further annihilates possible interpretations, creating a tension between the void and the concrete.

Although monochromatic, Liu’s work lacks the opacity and heaviness generally attributed to the color black.  Instead, the repeated, layered marks of graphite are almost ethereal, resulting in textile-like surfaces with varying degrees of transparency. We could potentially place the paintings under the umbrella of post-minimalism, but there is a softness to them, an unlikely marriage of mathematical precision and organic texture. Unlike minimalism, which favors literal objects, Liu’s work moves into an immaterial realm. Titling his 2012 Shanghai show “Infinite Line,” Liu is clearly fascinated with the concept of line in space. While, at first glance, there’s nothing digital about them, his lines are made with rulers and based on mathematical models. According to the laws of geometry, any one line in space yields infinitely many points, while two parallel lines eventually meet at a point of infinity. There’s a feeling that these lines reach beyond their frames, their canvases warping in the direction of the gallery’s unfilled space. Experiencing Liu’s work is like trying to remember , a word on the tip of your tongue, simultaneously on the threshold of a vast expanse and at a dead end.

“Liu Wentao: Xuan” is at White Space, Beijing, until October 19.