This research report has been prepared to provide an overview of the Japan 2050 Low Carbon Navigator (Low Carbon Navigator), how it works, and what its assumptions are. Section I introduces the Low Carbon Navigator to the audience, providing the background of the initiative as well as a description of the model. Section II explains the fundamental model, its structure as well as the calculation procedures. Section III describes the underlying society scenarios (i.e. the assumed structure of the economy and society) that will affect Japan’s energy consumption and greenhouse gas (GHG) emissions. Sections IV and V explain the trajectories/levels that have been set out for the supply- and demand-side sectors1. The users of the Low Carbon Navigator will be able to quickly refer to these sectoral descriptions to see the assumptions and outcomes under each level. Each one-page description provides an introduction to inform the audience about the current status of the sector. This is followed by illustrative definitions of the trajectories/levels, including indicative results by Low Carbon Navigator simulations. The text of the descriptions have been intentionally kept short, simple and specific so that it can be used by a wide range of audience. The associated charts and figures make the descriptions more vivid and easy-to-understand. The users of the Japan 2050 Low Carbon Navigator are recommended to look into these one-page descriptions of the sectors to get a clearer idea about the levels/trajectories setting. Section VI provides two example pathways under different levels setting to illustrate how to interpret the results generated by the model. The scenarios are presented side-by-side so that they can be compared easily by the readers. Section VII concludes the report and informs the readers about the limitations of the Low Carbon Navigator.