  We provide an alternative definition for the familiar concept of regular
singularity for meromorphic connections. Our new formulation does not use
derived categories, and it also avoids the necessity of finding a special good
filtration as in the formulation due to Kashiwara--Kawai. Moreover, our
formulation provides an explicit algorithm to decide the regular singularity of
a meromorphic connection. An important intermediary result, interesting in its
own right, is that taking associated graded modules with respect to (not
necessarily canonical) $V$-filtrations commutes with non-characteristic
restriction. This allows us to reduce the proof of the equivalence of our
formulation with the classical concept to the one-dimensional case. In that
situation, we extend the well-known one-dimensional Fuchs criterion for ideals
in the Weyl algebra to arbitrary holonomic modules over the Weyl algebra
equipped with an arbitrary $(-1,1)$-filtration.
