This is the first part of a four-part series this week, where I provide some guidance on some key questions about Modern Monetary Theory (MMT) that various parties in Japan have raised with me. The public discussion about MMT in Japan is relatively advanced (compared to elsewhere). Questions are asked about it and answered in the Japanese Diet (Parliament) and senior economics officials in the central bank and government make comments about it. And political activists across the political spectrum are discussing and promoting MMT as a major way of expressing their opposition to fiscal austerity in Japan. The basics of MMT are now as well understood in Japan as anywhere and so the debate has moved onto more detailed queries, particularly with regard to policy applications. So as part of my current visit to Japan, I was asked to provide some guidance on a range of issues. In my presentations I will be addressing these matters. But I thought it would be productive to provide some written analysis so that everyone can advance their MMT understanding. These responses should not be considered definitive and more detail is available via the referenced blog posts that I provide links to.