Despite an iterative workflow and common characteristics, board game design differs from its video game counterpart in the tasks and frequency with which digital technologies are leveraged. This study presents “Prototypical”, a software application explicitly intended to support the board game design process. “Prototypical” provides modelling, simulation and analysis features for prototyping and developing individual board game mechanics. Three examples demonstrate its current capabilities and the performance of the Monte-Carlo Tree Search artificial intelligence agent, while a user study involving five participants and the System Usability Scale survey identifies the need for user interface improvements.