Coins

In my current classic D&D campaigns, I’ve switched to a “silver standard”, and I describe the coins this way:

By Arichis at en.wikipedia [Public domain], from Wikimedia Commons

• Gold is treasure
• Silver is money
• Copper is change

Which is really the whole point of the change. Having the PCs start the game with 100 gold coins to spend (even if it really only represents their net worth rather than actual coinage), dampens the impact of finding a coffer of gold coins.

But I find that the 1gp:10sp:100cp ratios (call it “tens, dollars, and dimes”) that I’m using—because it made converting from standard values to mine easier—don’t quite give that feel. I’m thinking 1gp:100sp:10,000cp (hundreds, dollars, and pennies) would better represent those distinctions.

One of the sources I like to borrow from is history. (Plus, it gives me an excuse to learn about history.) So, I took a look at the coins during the reign of Edward III and Roman currency. Neither of which really have anything close to a 1:100:10,000 trio to use as a model. Which is disappointing.

Maybe 1:20:400 would be sufficient? Although, failing the history reality-check doesn’t count 1:10:10,000 out completely.

Either way, it makes the math between classic D&D and my D&D values more difficult.

The reciprocal mechanic

For an RPG resolution mechanic, I like coin pools. I like that it is open-ended on the high end. i.e. There’s no upper limit on the scores that determine how many coins are in the pool. I like that it has diminishing returns. i.e. Each coin added to the pool increases the probability of success by a smaller increment than the previous coin.

What I don’t like is that the increments still seem a bit too big.

To get smaller increments, what if the chance of failure equals the reciprocal of the score? e.g. A score of 4 would grant a 1/4th chance of failure. Thus, a 3/4 chance of success.

OK. I like those numbers better, but how do we do this with dice?

One way is to roll a die with a number of sides equal to the score being used. Anything except a 1 means success.

And you thought people complained a lot about DCC using d3, d5, d7, etc.

It’s really not that bad, though. Just choose the next bigger die you have and reroll results higher than the score. e.g. For a score of 5, roll a d6. 1 = failure; 2 to 5 = success; 6 = reroll.

It gets a bit annoying for scores between 12 and 20. At 13, if you’re rolling a d20 and rerolling 14s and above, you’ll be rerolling 35% of the time. Having a d14 and d16 helps out. A d24 and a d30 help for scores over 20. Over 30 starts calling for some creative solutions. At 30, though, we’re up to a 96.7% chance of success, and 2 to 30 is a decent range for scores. Probably more than is really needed.

Alternatively, you could use drawing chits or cards or stones. Put a number of stones equal to the score in a bag. One of them should be a different color than the rest. Draw out the odd stone and it’s a failure.

Any other method?

Coin pools

I’ve heard a few game designers say that, as a base line, dice rolls should succeed at least half the time. That got me to thinking... What if we start with a base 50% chance and each increase moves it half-way towards 100%? Is there a simple dice mechanic for that?

Yes, there is, and it was already sitting on my RPG shelf. Prince Valiant, The Story Telling Game (1989) by Greg Stafford uses coin pools. The player flips a number of coins and, if any come up heads, it’s a success. (Sometimes you want more than one heads, but let’s ignore that for now.) The higher the character trait being tested, the more coins the player tosses.

(Since I usually have more dice than coins these days, I just use dice and “even” counts as “heads”. Don’t grab those odd dice—d3, d5, d7—though. Loan them to your opponent.)

It’s a nice, simple mechanic. It is open-ended (on the “high” end), which can be nice. And the probability increments start course and only get finer as you need it to.