  The statistics of random band--matrices with width and strength of the band
slowly varying along the diagonal is considered. The Dyson equation for the
averaged Green function close to the edge of spectrum is reduced to the
Painlev\'{e} I equation. The analytical properties of the Green function allow
to fix the solution of this equation. The former appears to be the same as that
arose within the random--matrix regularization of 2d-gravity.
