  The Belle II experiment at the SuperKEKB collider in Tsukuba, Japan, will
start physics data taking in 2018. It is planned to accumulate an e+ e-
collision data set of 50 /ab, about 50 times larger than that of the earlier
Belle experiment. The software library for the new detector will use GEANT4 for
Monte Carlo simulation and is an entirely new software and reconstruction
system based on modern computing tools. Examples of physics simulation
including beam background overlays will be described.
