  We present a newly enhanced version of the Monte Carlo Shell Model method by
incorporating the conjugate gradient method and energy-variance extrapolation.
This new method enables us to perform large-scale shell-model calculations that
the direct diagonalization method cannot reach. This new generation framework
of the MCSM provides us with a powerful tool to perform most-advanced
large-scale shell-model calculations on current massively parallel computers
such as the K computer. We discuss the validity of this method in ab initio
calculations of light nuclei, and propose a new method to describe the
intrinsic wave function in terms of the shell-model picture. We also apply this
new MCSM to the study of neutron-rich Cr and Ni isotopes using the conventional
shell-model calculations with an inert 40Ca core and discuss how the magicity
of N = 28, 40, 50 remains or is broken.
