  The results of complementary tests of perturbative QCD in DIS at large
centre-of-mass energies at HERA are presented. The analysis of event shape
variables allows for the investigation of approaches to understand aspects of
non-perturbative QCD such as the formation of the hadronic final state. The
strong coupling constant, $\alpha_s$, is extracted from both inclusive jet
cross sections and dijet rates and is found to be competitive with the world
average.
