Shatterheart is a d20 system that takes the idea of ‘bounded accuracy’ serious. We have deeply analyzed the math of d20 systems and understand the reasons why character and monsters poorly scale. By adopting a few simple principles in the core math we can avoid combat become hit point slog fests that can take an hour or more, especially at higher levels. This has required rewriting, often from scratch every class, class feature, monster and spell. We have fully developed around 550 monsters and spells each. We have rewritten each of 10 classes over 5 times to ensure each is incredibly exciting to play at the table and customize through levelling. The core system is simple in terms of dice mechanics and character creation. However, there is an incredible depth of abilities and spells for character customization. Combat is tactical using a n action points system, but much simpler and quicker to resolve than Pathfinder, multiple attacks per round are abandoned, you attack once, but use tactical choices to try and max out your damage and outcomes. You need to because monster hit far harder and unless you outwit and outplay them you will quickly die. You will be amazed how quickly combat resolves, and how tense and exciting it is. Now is time for extensive playtesting, broadening out for the limited in house playtesting so far, We fell that some recent systems have lunched too soon before a full system playable for a long term campaign is ready.