The q-Painleve V equation and its geometrical description

We study the q-Painleve V equation which can be obtained from the degeneration of the q-P-VI (in the form of the asymmetric q-P-III) equation and present its geometrical description. Based on the bilinear formulation we obtain the equations for the multi-dimensional tau -functions of q-P-V (in the form of nonautonomous Hirota-Miwa systems) which lives in the weight lattice of the A(4) affine Weyl group. This geometrical approach furnishes in a straightforward way the Miuras and the Schlesingers of q-P-V.