I really like to use random tables, but sometimes you find a resource that doesn’t match your dice evenly. This is a how to use a standard set of polyhedral dice for a selection from lists that were not made for random tables and do not divide easily.
While picking a random month of the year is easy to do with a d12 or the picking of a random element would take a four-sided die (assuming classical Aristotelian elements), the picking of a chapter at random when you have 39 chapters is less intuitive.
Three predominant techniques are used, often together to handle these odd-numbered lists. For this discussion I will assume the complement of four, six, eight, ten, twelve and twenty sided dice. The standard notation of d for dice followed by the maximum number on the die will be used, (meaning d4 for a four-sided die)
Technique the First: Reroll extras.
For a list of 5 items: wood, water, gold, fire and earth how do you pick one at random without a d5. The answer is use a d6 but reroll every value over 5. This would work just as well for a d20 and reroll extra values, except for the need to reroll a lot more often.
Technique the Second: Roll multiple
Say you want to pick a random catch phrase from your favorite book for your character. The book has 100 chapters. Without a d100 you can roll a d10 and a d10, one being the tens place and the other the one’s place in the number.
Technique the Third: Modify rolls
Say you want to roll a number between 0-3. But most dice only roll between 1 and a number, you can add simple mathematics to alter the result. So for 0-3 you would roll a d4-1 and subtract that one. For a roll 1-3 you can do a d6/2. Division and multiplication really should only be used on lower number rolls to make them easy to mentally calculate.
And finally combine the three.
So for a chapter with 39 lines, roll a d4 and subtract one for the tens place and d10 for the ones place. Rerolling the d10 of 0 if the d4 is 4.
Or a bit more complex. For a chapter with 150 lines do a d6/2 to pick which set of 50, then a d6-1 (reroll 6) to pick a number 0-5 for the tens a d10 for the one’s place.
Say you have a cleric and you want to use some lines for the bible altered to fit your fantasy world lore.
|17 Books||Matthew has 28 chapters||Chapter 28 has 20 verses|
|Roll 1d20, rerolling 18-20||roll a d30 and reroll 19-30, or roll a d6 for tens place and d10 for ones, divide the d6 result by two and if the combination is greater reroll it.||roll a d20|
This renders the verse below which can be molded and reused:
Teaching them to observe all things whatsoever I have commanded you: and, lo, I am with you always, even unto the end of the world. Amen.
This gives me the quick statements for the cleric to use repeatedly; Teach them. He is always with you. To the End of the world.