, "Full-Size Preview" работает даже для незарегистрированых людей, если я не ошибаюсь.
А в целом, вот основная идея (копипаст из дока):
The idea behind the system is that one of the five abstract gaming strategies is chosen by the participants for each round of the game. Any strategy is stronger than two other strategies, and weaker than two other ones. An appropriately chosen strategy could provide a +2 or even a +5 bonus to a gaming roll:
d20 + Ability mod. + Prof. bonus + Strategy bonus
1. Characters choose one of the strategies in secret.
2. The strategies are revealed and the strategy bonus is determined.
3. Characters make their rolls.
4. A player who rolled higher, adds 1 point to the score. If his or her roll is at least twice as high as an opponent’s, add 2 points instead.
5. The first player, who gets 5 points, wins.
Плюс правила по мухляжу, подсказкам и помехам, и несколько практических примеров прилагаются.