Niklaus

Not completely sure, but going from how it's worded it seems like the same roll that you get hit on you have a chance of healing up from it. So it kind of works like a "chance damage mitigation?" O_o

as far as I know you use the craft roll for the regen...further info can be asked to the PSTs

It works as a "chance damage mitigation" for light armour users who are not able to get the damage mitigation that heavy armour users do, in turn they also have other enchants that assist them in constantly landing their attacks rather than taking them.