  We consider a desingularization Gamma of a Richardson variety X_w^v=X_w \cap
X^v in the flag variety Fl(n)=GL(n)/B, obtained as a fibre of a projection from
a certain Bott-Samelson variety Z. We then construct a basis of the homogeneous
coordinate ring of Gamma inside Z, indexed by combinatorial objects which we
call w_0-standard tableaux.
