Since the discovery of new Stokes’ line by Berk, Nevins and Roberts (1981), WKB analysis of higher order equations is known to be tough. That is, due to necessity of new Stokes lines, which never appear in second order case, it is difficult to find out the complete Stokes geometry for a given equation. Still, a probable recipe to obtain the Stokes geometry is known, by Aoki, Kawai, Takei et al.
In this talk, starting from the BNR equation, I explain the recipe. Then, we are going to examine it through several concrete examples with the aid of (exact) steepest descent method. Also I give some comments about connection formula beyond a Stokes line.