Reclaimed ground of Kobe Port Island liquefied during the 1995 Hyogoken-Nambu Earthquake. That ground had been created by reclaiming decomposed granite called Masado. In this research, shear and liquefaction characteristics of Masado were examined by conducting monotonic and cyclic triaxial tests. A similar experiment was also conducted on Toyoura sand for comparison. Differences in shear and liquefaction characteristics between Masado and Toyoura sand were demonstrated on the basis of triaxial test results. Three types of Masado were artificially created to represent different physical properties of Masado obtained from Kobe Port Island. Effects of fine content, breakage of particles, and grain size distribution on liquefaction behaviour were discussed to explain the peculiarity of Masado in a loose state. Accurate stress-dilatancy relationships of Masado and Toyoura sand, which are necessary to make a numerical model, were also demonstrated.