I used to prefer heavy bag without gloves....I am forced to minimize my closed fist strikes now a days though, due to an injury, but it doesn't take much of a chalice to withstand it IMO...of course it's a "results may vary" sort of thing tooActually, it's easier to break your hands or cut them in a fight then you might imagine. Unless you have chalice's built up on your knuckles. It's better to use a back fist, palm heel, etc. If you are throwing strikes to the head, chin, etc. I'm not just talking out of my ass either. Try hitting a heavy bag with no gloves. See how long it takes to tear the skin from your knuckles. When I studies Martial Arts, we used to condition our hands on special made boards.