When you say "slot is checked very rarely", does that mean that most checks ignore "slots" entirely and just look at a target's overall AC (or some other measure), or are you saying that the ring slot in particular gets checked very rarely (relative to other slots)?

Every blow checks a slot, assuming the target has a humanoid build. Unless a 'stop' occurs, you don't see this, since it would get spammy, and we don't want to get into the mess of "I hit him in the face! That should be QUINTUPLE DAMAGE!" systems, which IMO tend to up-emphasize luck too much.

The ring slots get checked extremely rarely, as in not worth caring about. I couldn't find a ring that counted as armor in a few tries, but theoretically a magicky-ring themed around defense could find its way in.

valguarnera@carrionfields.com