The d6 Principle (Optional Rule)

If the Referee wants a more nuanced method of determining the likelihood of success when a player attempts to do something, they can apply The d6 Principle. As a general rule, actions attempted in the dungeon are successful on 1-2 on 1d6, as noted above. The Referee then modifies this chance of success based on the following circumstances:

Modifiers

Attribute: If one of the PC’s attributes is particularly applicable to the roll, apply its modifier, reducing the chance of success by -1 if the attribute is 6 or lower and increasing the chance of success by +1 if the attribute is 15+.
Race: When a PC’s race is typically insightful into a matter or has some natural skill, add a +1. Dwarves might recognize shoddy stonework or be able to identify veins of ore, while Elves might better identify strange plants or signs of natural animals, and Halflings might recognize spoiled food or signs of someone having fled the area after having hidden themselves.
Class: If the PC’s class would reasonably be very knowledgeable about the task at hand, add +1 to the chance of success. For example, Fighters might recognize weapon qualities or signs of a recent battle, while Clerics might recognize the nature of a divine altar or be able to identify religious symbols, and Magic-Users might know strange bits of arcane lore or esoteric history.

Cumulative Modifiers

For each of the three categories that is applicable, the Referee applies the appropriate modifier. These modifiers are cumulative. This means a character who is attempting something where they have no applicable areas and a low attribute, they might only have a 1-in-1d6 chance of success since the base chance is 1-2 and their attribute modifier is -1.

Example

But in the case of a Dwarf Fighter with an Intelligence of 15+, they might have a 1-5 in 1d6 chance of identifying the strange metal used to craft a sword they’ve discovered; 1-2 on 1d6, with +1 for being a Dwarf (who is skilled at identifying metalwork), +1 for being a Fighter (who likely knows a lot about swords), and +1 for their high Intelligence.

Referee’s Final Call

In the end, the d6 Principle is a guideline for Referees and they are the one who makes the final call about when modifiers for high attributes, race, and class are appropriate.

Target 5

For groups that find rolling higher more intuitive, use this ascending version of The d6 Principle. Instead of counting a chance of success from the low end of a d6, the player rolls 1d6 and succeeds on a 5 or better.

Apply the same circumstances as modifiers to the die roll: add +1 when an applicable race, class, or strong attribute would help. If an applicable attribute is especially poor, apply -1 instead. These modifiers are cumulative, and the Referee still decides which factors apply.

For example, a Dwarf Fighter with an Intelligence of 15+ trying to identify unusual metalwork would roll 1d6 +3, needing a final result of 5+.