6d6 is a generic system designed to be adapted quickly into any setting. The core of the game are a character's advantages and their potential. Advantages are life traits like Brawn, skills like Diplomacy or equipment like Binoculars. To take any action, a character spends potential to use their advantages.
And that's it. Those three sentences form the fundamentals of the game. You can find a quick start of how to play 6d6 here: http://6d6rpg.com/store/6d6rpg.shtml
Living Document:
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If you have registered your 6d6 product, you will always have free access to the latest PDF no matter how many versions we have released. That's a promise.
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Generic Modern:
"The Generic / Modern setting fits into a wide variety of genres. Almost any type of adventure involving everyday humans set in the 21st century can be played using characters created with these paths. As humans have not changed much in the last 10,000 years and will probably be the same in 10,000 years, many paths will also fit with historical and future settings. "