Would anyone know if game mechanics are protected by copyright laws? And if so, why are there so much games that seems to be able to copy D&D rules without being squeezed? Thinking thru the issue, i see a couple of scenarios in the usage of game mechanics. 1) Complete - Uses just the full game rules, and values 2) Variation - Uses the game mechanics with some variation to rules and a few twitches to the values. i.e. Str 18 gives +6 instead of +3 3) Name Change - Just like 1 except for change in names. I.e. Muscles instead of Strength. 4) Concept - rolling a hitroll against an opponent's defences plus strength bonuses. I would assume that 1 would infringe copyright, but what about 2, 3, and 4? Thanks

Copyrights only apply to creative works, such as literature, models, and such. They do not apply to algorythems (which is as close as an RPG ruleset comes); that is the realm of patents.

Honestly, I would think that D&D could have patented their ruleset and protected themselves that way. As they presumably didn't, it's fair game for all.

Thus I believe (and I'm not an IP lawyer) that 1-4 will not violate any copyrights.