The basic idea is that everyone has an Area of Control (AoC). This replaces reach, attacks of opportunity/opportunity attacks, flanking, and a few other things. The basic AoC looks like this:
The space taken up by the creature (G) is green. The AoC is blue.- G gets a free attack on anyone moving out of a blue square.
- A melee attack on G from anywhere outside of a blue square is at +1. An adjacent attack on G from anywhere outside of a blue square is at +2. This replaces flanking.
- Reach weapons change a characters AoC dramatically. A longspear, for instance, might give a character an AoC like this:

- A character can change the orientation of their AoC on their initiative.
- A flat-footed character has no AoC.
- Large+ creatures can have uniquely shaped AoC (and take up non-square spaces) to reflect their physiology and abilities.
- Feat ideas:
- Most feats building off of flanking, reach, etc. will have obvious correlates.
- Allow a character to change the orientation of their AoC as an immediate action in response to a successful attack.
- Allow a flatfooted character to have an AoC of one adjacent 5' square.
- Allow a character to treat one extra square adjacent to them as part of their AoC.
