[en] In this study, we performed the coupling of the MARS 1D module and MASTER to develop the 'system thermal-hydraulics - 3D reactor kinetics' coupled calculation capability. The new feature has been assessed with the OECD NEA MSLB benchmark exercise III simulations. Four different calculations were carried out for comparisons: - 1D base case calculation: MARS 1D Module + MASTER, - 1D refined calculation: MARS 1D Module + MASTER + COBRA-III/CP, - 3D base case calculation: MARS 3D Module + MASTER, - 3D refined calculation: MARS 3D Module + MASTER + COBRA-III/CP. The comparison of the results shows that the coupled calculation using 'MARS 1D module and MASTER' worked well as intended and that the results were very similar and consistent with those of the MARS 3D module. In particular, it is shown that the new feature can be utilized efficiently for analyzing the transients, which are characterized by multi-dimensional reactor kinetics and one-dimensional core thermal-hydraulics