When characters need to determine the outcome of an event which is in doubt, there are 4 systems:

• Attack Roll: use the THACO calculation or look on the Attack Tables, reference attacker's level or HD vs target AC and roll 1d20 to get that number or higher to score a hit and inflict damage. The bonuses “to hit” will be much fewer in number than in other members of the D&D constellation of games.

• Saving Throw: to avoid a magical or similar devastating attack like poison or being knocked off a horse by a polearm, roll 1d20, add your level to the roll (and any special bonus from Wisdom, Class or Species) and score 17 or better.

• Adventuring Skill: if you have a particular skill that most people do not, you will roll 1 die, determined by your experience level, and roll a 3 or better to succeed. The chance for non-skilled people to detect secret doors and hear noise is a gimped version of this method, requiring a 5 or 6 instead of a 3.

• Ability Check: if a task or hazard arises that most people would have some chance to overcome, regardless of training or experience, the Judge will pick one of the Ability Scores that is appropriate and tell you to roll 1d20. If you get your Stat in that Ability Score or Less on a d20, you succeed. If the circumstances are very difficult, the Judge may call for a roll on 1d100 instead of 1d20 to succeed. Morale follows this system, with NPC's having a Morale Score, sort of a 7th ability score.