In this paper we study the boundary value problem for the equation div D(∇u)∇ div |∇u| p−2 ∇u + β ∇u |∇u| + au = f in the z = (x, y) plane. This problem is derived from a continuum model for the relaxation of a crystal surface below the roughing temperature. The mathematical challenge is of two folds. First, the mobility D(∇u) is a 2 × 2 matrix whose smallest eigenvalue is not bounded away from 0 below. Second, the equation contains the 1-Laplace operator, whose mathematical properties are still not well-understood. Existence of a weak solution is obtained. In particular, |∇u| is shown to be bounded when p > 4 3 .