  We show that string theory with Dirichlet boundaries is equivalent to string
theory containing surfaces with certain singular points. Surface curvature is
singular at these points. A singular point is resolved in conformal coordinates
to a circle with Dirichlet boundary conditions. We also show that moduli
parameters of singular surfaces coincide with those of smooth surfaces with
boundaries. Singular surfaces with saddle points indeed arise in the strong
coupling expansion in lattice QCD. The kind of saddle point, which may be the
origin of a singular point we need, is of infinite order.
