In traditional Japanese timber structures, nuki-column joints are used as seismic elements. However, the elastic stiffness of their moment resistance performance is rather small. In this research, hardwoods were used for nuki in three ways to improve the performance of the joints. Moment resistance tests of the joints were conducted to evaluate their structural performance and clarify the differences depending on the wood species, the nuki cross sections, and reinforcing effects of hardwoods discussed. In some specifications, it was shown that using hardwoods for nuki improved the structural performance of the joints. A significant effect was observed on some characteristic values of the joints.