Skip to Content

Diceless Fate/Fudge Mechanic for RPG

13 replies [Last post]
Toa Lewa
Toa Lewa's picture
Joined: 10/31/2013

Call me weird, but since my sister and I don't have much time to play RPGs, we typically do it while I'm driving in the car of all places. We never have dice with us, and as the GM, I can't safely roll dice as I drive.

I came up with my own very rules light statless system. In my head, I calculate the likelihood of failure and give my sister a ratio. I then will secretly pick a number, and if my sister can guess the number, the skill check succeeds. For example, let's say she is trying to pick a lock. I might tell my sister 3 out of 5. I will secretly pick one number between 1 - 5 (let's say I picked the number 2). 3 out of 5 means she has three guesses. She picks 1, 3, and 5, and fails. Later, she has to walk a tight rope. I might say, 1 out of 13. I pick the number 8. She can pick any number between 1 and 13, and she guesses 8. Her character successfully makes it across the rope.

I'm getting tired of this mechanic, and I want to introduce stats while still having a very simple resolution system. I've been reading Fate, and I really like how stats are ranked as Average (0), Fair (1), Good (2), Mediocre (-1), etc. I like the Fudge Dice mechanic, where you roll 4 dice with pluses, minuses, or blanks, which raises or lowers your stat to compare against the target difficulty. The obvious problem is, Fudge uses dice!

I want something simple like my mental system above but I also want it to simulate Fudge rolling. The closest I've gotten is doing Rock, Paper, Scissors four times in a row and adding up the results (win = +, lose = -, and tie = blank). Although this would create almost the same result, it sounds tedious. My other idea was to mentally assign a range of 12 numbers either a +, -, or blank. My sister would pick 4 numbers, and the results would add up, but this idea is going to put a strain on my memory. To create randomization, I will need to assign the values differently each time, and again, this will be tedious.

Does anyone have any ideas? Thanks.

radioactivemouse's picture
Joined: 07/08/2013

If you're going to use a fudge dice mechanic without using dice, the answer I've thought up is having cards represent the rolls. Since there are 4 6-sided dice, create a deck of cards that has 8 "+", 8 blanks, and 8 "-" (a card representing each side of each die) A player, when they need to "roll", just shuffles the deck and reveals 4 cards from the top of the deck as if they rolled a set of FATE dice.

Joined: 05/11/2010
If you have one hand, you

If you have one hand, you could secretly extend a portion of your fingers. She does the same. Any that match (you both are extending your index finger) counts as a +. Hard to have minus or blank with that.

Your ratio idea could work with some modification. What about picking a "bad" number and a "good" number. Hitting the good number is really good, hitting the bad number is really bad, and falling between them or being on opposite sides is neutral. If it's 1 to 10, you could pick 5 as bad and 9 as good. If she chooses 5 it's really bad, 9 it's really good, 8 or 10 are pretty good, 6, 7, 4, and 3, are pretty bad; and 1,2 are neutral. It's a little bit fuzzy with how you shade the region between the bad and the good number so that needs some work. (For instance I made 7 bad - it's halfway between them but still a little too close to the bad number for my liking) But you only have to remember 2 numbers and you might get the gradiation you are looking for.

questccg's picture
Joined: 04/16/2011
IDK why all the problem...

Why not just let your SISTER "Roll the FATE dice" into a tupperware container.

Once this is done, you can ask her:

1. How many "+"?
2. How many "-"?

Forget about blanks since they are "0".

Why make such a big issue out of this??? I simply don't understand...!

Maybe I did not understand your problem... But FATE dice make it easy to calculate and it doesn't have to be the DM that rolls.

If you need to distinguish between 2 people, well then have a set of BLUE "FATE" dice and a set of RED "FATE" dice.

Then you ask:

1. How many BLUE "+"?
2. How many BLUE "-"?
3. How many RED "+"?
4. How many RED "-"?

Simple system... don't over-complexify a simple problem IMO.


bbblackwell's picture
Joined: 10/23/2013
Me too

Yeah, I'm also not sure I understand why she's not rolling the dice... hahaha I'm sure there's a good reason, though.

I think you've hit the wall in terms of what's possible without physical components. You've handled it very well so far, but anything we come up with would probably just be a variation on that theme -- you think of something, and she tries to guess.

Of course you could embrace those variations -- numbers, letters, colors, farm animals, heck, even sports trivia! If she can guess who hit the game-winning homerun to win the 1993 World Series, her black arrow hits Smaug in the sweet spot!

I'll keep thinking, and will return to save the day if I think of anything. I'm 3 sessions into a two-player GM-less RPG campaign right now, and I had to work out many unanswered questions about circumventing the established system, so I feel your pain!

P.S. Anyone who can answer that trivia question without using the internet gets a cookie. Not from me, though, so don't ask.

X3M's picture
Joined: 10/28/2013
If rolling the dice is a

If rolling the dice is a hassle. Why not construct a wheel (of fortune). 1 spin would be all you need.

questccg's picture
Joined: 04/16/2011
Wheel of Fortune!

X3M wrote:
If rolling the dice is a hassle. Why not construct a wheel (of fortune). 1 spin would be all you need.

Make the wheel with having six (6) values: 2x Blank, 2x "-" and 2x "+".

That's an even easier option... Great input Ramon!

pelle's picture
Joined: 08/11/2008
There are actually official

There are actually official FATE decks you can buy to draw from instead of rolling dice. But they have more (81) cards because they preserve the probabilities of the dice:

But if OP's sister has a smartphone I would just recommend using a FATE dice roller app instead of trying to come up with something more clever than that. Rolling real dice is more fun, but without the real dice (like in a car) I would just use a phone.

richdurham's picture
Joined: 12/26/2009
System goals

TL;DR - What follows is long winded way of "Each pick a number in a range and subtract them, see if the result is lower than an ability score"

Do you want the + and - of the FATE system because it also includes a degree of success or failure, or perhaps because of the bell curve the multiple dice provide?

I love the benefit of fudge/fate that it averages out to 2/3 of the rolls are within 1 of your skill level, with a nice bell curve away from it.

Here's a nice table from Fudge dice probability tables n is the dice roll, P(n) is the number of combinations of those rolls that end up with that result, P(n-) is the % chance of rolling that number or LOWER, and P(n+) is the % chance of rolling that number or HIGHER.

n P(n) P(n-) P(n+)
-4 1/81 1.235 1.235 | 100.000
-3 4/81 4.938 6.173 | 98.765
-2 10/81 12.346 18.519 | 93.827
-1 16/81 19.753 38.272 | 81.481
0 19/81 23.457 61.728 | 61.728
1 16/81 19.753 81.481 | 38.272
2 10/81 12.346 93.827 | 18.519
3 4/81 4.938 98.765 | 6.173
4 1/81 1.235 100.000 | 1.235

Look at that sweet, sweet curve.

The system you're using now is great - so it makes a good base to change in order to get the bits the Fate/Fudge dice give.

  1. The non-linear curve of results
  2. Player ability scores
  3. Degree of success or failure?

Okay,It's not hard to replicate a semblance of this -

  1. Your sister will have an ability score from 1 to 5 (really, a 5 is dramatically better)
  2. I don't think you need to replicate both sides of the curve; just having a curve at all is enough. So we'll do this: each of you chose a number between 1 and 6 and subtract them (always greater-lesser to get only positive numbers).
  3. Any result LESS than your sister's ability score is a success. A perfect match = success with a bonus. Equal to the ability score = success at a cost (like FATE), and greater than the ability score = failure.

You can adjust your sister's ability score based on the difficulty of the task. Or you could, if you wish, make "harder" tasks pick from a larger range, like you do now (a harder task you would both pick between 1 and 10, for instance).

This will give you a curve rewarding precision, as there are dramatically fewer numbers further away from 0. Also a use of ability scores that provides the range of precision she'd need to be successful. You can use the difference between ability score and result (eg. ability was 3, result was 1) to indicate degree of success for story telling. (winning by 2 better than winning by 1).

Joined: 07/26/2015
This is a really neat way to

This is a really neat way to simulate probability without hands!
So neat!
Like other people have said, cards are good if you want "good probabilities", but the purity of this system. If you have good memory, you don't need ANYTHING to play.

richdurham's method seems like a good way to approximate a curve.
"pick two random numbers and subtract" will give you a triangular curve, with lower possibility of larger numbers and highest possibility of 1, and a middling probability of 0, as illustrated in this chart.

0 1 2 3

1 0 1 2

2 1 0 1

3 2 1 0

Also, I think mentally, people tend to pick numbers closer to the middle, but not exactly middle, which will actually "round out" the curve to be closer to the fudge dice binomial curve, which is nice.

The big thing with this method is that your sister can choose to pick in the center (which will result in a smaller expected result). The mathematical way to prevent this is to use modular arithmetic, but that destroys the nice triangular curve.

Your method of picking a number in k and guessing n times gives you a flat probability n/k. If you change your target number every turn, you get the nice probability curves (1/k)^n, which you can view here:

There is some mental arithmetic, but you can offload it to your sister. Just keep making up numbers. The bigger problem is that for large k, the probabilities are scrunched to the left. (n=5, k=5, p=0.2). I would simply invert success and fail, so that there is a good chance of success anyways.

I ran the numbers (puts on math hat). Say for tightrope walking, you guess from 1-3, guess four times fail if you guess CORRECTLY, which has 0.2 (one in five) chance of success. With agility, you can fail once, and this suddenly jumps the success chance to 0.6 (three in five). With two chances to fail, the chance of success goes up to 0.9.

It seems easy enough to use, but the probability curve is not really intuitive. You might need some time to get a feel for how hard the tests are.

Toa Lewa
Toa Lewa's picture
Joined: 10/31/2013
Awesome Idea!

richdurham wrote:
**TL;DR - What follows is long winded way of "Each pick a number in a range and subtract them, see if the result is lower than an ability score"**


This is exactly what I was looking for. The cool thing is, there are 5 ability step levels in this. My system of choice is Savage Worlds, and there are five skill levels in that system. I think it will mesh well with the way I normally think of skills and run a game. For adjusting difficulty, I think I'll go with your suggestion of increasing the number range.

Thanks for the help!

Toa Lewa

richdurham's picture
Joined: 12/26/2009

Cool, glad to help

pelle's picture
Joined: 08/11/2008
One worry I would have about

One worry I would have about picking numbers and just subtracting without module to get low numbers is that you get into a kind of odd game-theory situation where obviously the player wants to pick a number in the middle to avoid risk of very low results.

Picking numbers trying to get a high result instead is slightly better because then the player at least has to alternate picking a very high or low number. But then the gm pretty much decides the outcome by choosing something in the middle or not.

And then both try to think about this and try to randomly pick numbers as fair as possible, but I think it would be difficult for the player (or gm) to get out of their head anyway that all numbers are not equal.

Would be interesting to hear if OP tries this how it works out after a while.

richdurham's picture
Joined: 12/26/2009
That's just one of a few problems

The other is that it's very easy to make situations that are impossible to succeed at, if the task is harder than the player's skill level.

An option to reduce the middling-effect is to make a perfect match an automatic failure rather than a success. To reduce the odds of that, I'd use numbers from 1-10 instead of 1-6. I think that'd give a better gradient for use in adjusting task difficulties, as well.

Personally I like the mind-game of it. If you're going to pick a number out of thin air, it might as well be an interesting choice!

Syndicate content

forum | by Dr. Radut