Treasure Codes: Thoughts on Quantity and Probability

This is Part Five in an ongoing series re-examining treasure types in OD&D and discussing a possible mnemonic replacement.

• Part One: treasure codes
• Part Two: coins
• Part Three: gems and jewelry
• Part Four: maps and magic items

Today’s topic: Dice ranges for treasure amounts and the probability of finding each variety of treasure.

I mentioned one way of sorting the treasure types in Part Three based on quantity. But we could also sort based on likelihood of finding maps or magic. Mixing the two methods and splitting off Type I as an outlier gives us six categories:

Types	Category Name	Examples
A1/A2	Active Treasure Collectors	bandits
A3	Active Waterborne Collectors	pirates
B-F	Standard Treasure Troves	orcs, ogres
G	Dwarven Hoard	dwarves
H	Treasure Hoard	dragons
I	Individual Items	rocs

Active treasure troves have generous quantities of gems and jewelry and high chances of magic items, although pirate treasures (A3) have no magic, only a map, which is why it’s separate.

Standard treasures have smaller quantities of all monetary treasure varieties and lower the chance of copper coins in a trove as you progress through the alphabet: 50% for Type B down to 0% for Type F. Oddly, the chance of a magic item being in a standard treasure trove increases as the number of items increases. It’s roughly a 10% chance for each item, excluding bonus items like potions and scrolls.

Dwarven Hoards have generous quantities of gold coin, gems, and jewelry, no other coin varieties, and follow the same pattern for magic items as Standard treasure troves.

Dragon Hoards have generous quantities of just about everything, but half the expected chance of finding magic items.

Individual Items have no coins and low quantities of everything, although the chances for gems, jewelry and a magic item are high.

Treasure types with generous quantities of coin, gems, and jewelry have at least 50% chance for each, while almost all types with standard quantities of a category have a chance less than 50%.

Other than that, there doesn’t seem to be any pattern linking quantity (dice) to chance of finding (probability.) But we can ignore that and create a link, just to make the mnemonics easier. I’ve already assumed all quantities are rolled with d6s only. Modifiers to the roll can be placed after the mnemonic code. This gives us:

• 3 Coyg = 3d6 chests of 1,000 gold coins each

• Jee-1 = 1d6-1 (or 1 to 5) pieces of jewelry, base value 100 coins each
• 4 Gee x10 = 10 to 60 gems, base value 100 coins each
• 2 Xu +p = any 2 magic items, plus one potion

The base probability for any of these is 10% per die rolled for quantity. So: 30% chance for the 3d6 chests of gold, 10% chance for the jewelry, 40% chance for the 10 to 60 gems, or 20% for 2 magic + 1 potion. No need to use percentile dice: roll a d10 instead, any result less than or equal to the number shown means that treasure is present. If the probability doesn't match the number of dice, use a target number prefix followed by a colon and the dice number:

• 6:3 Coyg 60% chance of 3d6 chests of gold
• 4:2 Xu +p 40% chance of 2 magic items + potion

Some options:

• d20 instead of d10: double target number
• 2d6 Drop 6s: Treat each 6 on a die as a zero, for number from 0 to 10. Target number is the same, but probability is no longer linear.

Next up: I finish this long series by translating the existing treasure types into mnemonic codes to create a new treasure type table.

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