CORE MECHANIC
Many games, including Chronology, use die rolls by default to introduce a random element of chance to the Guide's attempts to succeed at many tasks.
Some games do not recommend Guides roll anything, recommending instead to work from previously considered courses of action.
The choice to use dice rolls for results or not remains with the Role-players and the Guide, based on their preference for planning or surprises.
Guides may choose to substitute other randomizers such as decks of cards as preferred.
Dice Needed
Obtain two pair of differently-colored six-sided dice, commonly called “d6”.
White and red six-sided dice are recommended and extremely common.
The colors white and red will be used in the examples below, but feel free to substitute any preferred colors instead since the order the dice roll matters.
Guides can gather dice from board games they may already have.
Guides can also purchase dice inexpensively at many toy stores or toy sections of pharmacies and discount stores.
Online retailers offer custom and specialized dice in all materials, colors, and numbering patterns imaginable.
Dice Rolling Method
Roll the two white six-sided dice and two red six-sided dice together.
First, add up the total of the white dice.
Second, add up the total for the red dice.
If using other colors, designate which color totals first before rolling.
Subtract the second (red) dice total from the first (white) dice total to find the final result of the rolls.
Chronology refers to this dice roll with the short-hand notation 2d6 - 2d6.
Roll 2d6 - 2d6 for a result between -10 to +10.
Results
The result will fall in the range of negative ten (-10) to positive ten (+10), centered on zero (0).
Variations
Chronology may call for several others variations of rolls using different numbers and interpretations of just six-sided dice.
Smaller Range
Roll 1d6 - 1d6 for a total between -5 to +5.
Simple Rolls
Roll 1d6 for a total between 1 and 6.
Roll 2d6 for a total between 2 and 12.
Roll 3d6 for a total between 3 and 18.
Roll 4d6 for a total between 4 and 24.
Dice As Digits
Roll 2d6 to generate a 2-digit number of 36 possibilities between 1-1 and 6-6 where the first digit is 1-6 and the second digit is 1-6.
Roll 3d6 to generate a 3-digit number of 216 possibilities between 1-1-1 and 6-6-6.
Roll 4d6 to generate a 4-digit number of 1296 possibilities between 1-1-1-1 and 6-6-6-6.
Circumstantial Advantage or Disadvantage
Many games include the concept of circumstances where one side has some “advantage” over the other “disadvantage” side.
In conditions of:
Major Advantage: roll 3d6 - 1d6 for a total between -3 to +17.
Minor Advantage: roll 2d6 - 1d6 for a total between -4 to +11
Minor Disadvantage: roll 1d6 - 2d6 for a total between -11 to +4.
Major Disadvantage: roll 1d6 - 3d6 for a total between -17 to +3.
Designers Notes
This core mechanic uses only common, easily-found six-sided dice rather than more specialist hobby dice.
Results fall into an intuitive -10 to +10 range, centered on 0 for average.
Results provide 21 discrete values which center exactly on only one value (0).
The traditional 3d6 range of 3-18 centers on 10.5, making both 10 and 11 “average” values with equal probability of occurring.
Results approximate a Normal Distribution (also called a Bell Curve) rather than a linear or ramped result.
Compare the graphs and tables for 1d6-1d6, 2d6, and 1d20 at anydice.com to see comparative results.
The 21 possible outcomes approximate 5% steps of a percentile system requiring ten-sided dice, aiding conversions from other role-playing games by simply dropping the zero result and multiplying the steps by five.
This method provides more “range” than the more common or traditional 1d6 or 2d6 systems.
Additionally, this avoids some of the diminishing returns or probabilities of various dice pool mechanics which tend to include specialist rules to compensate.
Finally, the 2d6-2d6 roll avoids a complex-to-apply step-die system.
Additional Resources
Dice Methods (darkshire)
Die rolling mechanics - d100 (darkshire.net)
Die Rolling Mechanics – Additive (darkshire.net)
Die rolling mechanics - multidie additive (darkshire.net)
Die rolling mechanics - roll under (darkshire.net)
Die rolling mechanics - step die systems (darkshire.net)
Die rolling mechanics - universal table games (darkshire.net)
Dice Mechanics - Dice Pool Games (darkshire.net)
Dice Rolling Mechanics - Miscellaneous system types (darkshire.net)
Miscellaneous system types- part II (darkshire.net)
Non-dice randomization (darkshire.net)
Dice mechanics - Implementation - safety valves (darkshire.net)
Dice mechanics – implementation – Effect (darkshire.net)
Dice Mechanics - Implementation - cutting down excess rolling (darkshire.net)
Mixing and matching dice - Pt 1 - ye olde systems (darkshire.net)
Mixing and matching dice - Pt 2 - the trend toward universalisation (darkshire.net)
D6 System (rpg)
Is it possible to produce a bowl shaped curve with dice rolls? (stackexchange)
2d6-2d6 as a base roll for roleplaying games (rogueleaf) 1)
A Treatise on Different Dice-rolling Mechanics in RPGs (wikidot)
Choosing Natural Adjective Ladders (eclipse)