Special polynomials associated with the K2 hierarchy

New special polynomials associated with the rational solutions of analogue to the Painleve hierarchies are introduced. The Hirota relations for these special polynomials are found. Differential - difference hierarchies for finding special polynomials are presented. These formulae allow us to search the special polynomials associated with the hierarchy studied. The ordinary differential hierarchy for the Yablonskii - Vorob’ev polynomials is given.