The Last Planner System (LPSTM)is becoming popular for project management all over the world. Though the practitioners are able to follow the concepts quite well, they sometimes find it difficult to develop the required processes and templates, particularly in organisations and environments where systematic planning practices are not that prevalent. Structured templates, simulations, or games for LPS are also not freely available in the open domain. A simulation exercise, COLPLASSE (COLlaborative PLAnning System Simulation Exercise), has been developed to cater to this felt need. COLPLASSE is based on simple Excel spreadsheets and uses work plans for developing Look Ahead Plans and Weekly planning over the many weeks required for project completion. It has provisions to simulate random delays due to inclement external environmental conditions or variations in productivity due to various causes. It computes PPC automatically and simultaneously draws continuous charts for PPC and Root Cause Analysis over the Project completion period. It is simple to use and with further improvements being planned, can develop into a powerful tool for training or simulation or actual use along with LPS. Further research is proposed to be done using this simulation with various groups to evaluate its capabilities for helping early practitioners to use LPS. © IGLC 2018 All Rights Reserved.