🎲 Systems of Chance

Updated at 2013-01-30 00:11

Most board and video games involve some degree of chance. Illusion of chance is created by some form of randomizing device e.g. dice, spinning tops, cards, computer program. Related to game design.


Dice notation is XdY, where X is how many dice you roll and Y is how many sides there is on a dice. Chances are not what they seem.

d6 = 17% chance for each.

2d6 = 17% chance for 7 2.8% chance for 12 or 2.

3d6 = 13% chance for 10 or 11. 0.46% chance for 3 or 18.

Fixed Roll: Roll a fixed number of dice with a fixed number of faces. The context changes what is the numbers you aim to get.

Skill To Pass: A roll of XdY is made, modifier for abilities is added. Example: (1d20 + stat modifier + skill modifier) > check difficulty

Skill to Pass With Quality: The better the passing roll is, the better the quality. Example: (1d20 + stat modifier + skill modifier) > check difficulty ... if over or equal to 20, critical strike. ... if less or equal to 1, critical miss.

Skill To Reroll: A roll of XdY is made, pass if over a set value. If fail, you can reroll Z times, depending on your skills Example: (1d20) > check difficulty ... try 3 times

Dice Pool: Roll a dynamic number of dice with a dynamic number of faces. The context changes how many dice you roll and may change what dice you use.

Skill For Dice: Skills tell how many dices to roll. Example: ((skill modifier)d6) > check difficulty

Skill For Faces: Skills tell what kind of dice to roll. Example: (2d(skill modifier)) > check difficulty

Skill For Bonus: Skills tell how many plus points to add to each roll. Example: (2d6+(skill modifier)) > check difficulty

Check Styles: After rolling, there are multiple ways to determine if the check is a success.

Total: Roll total sum must go over or below the check difficulty.

Best: Only read a number of the top scoring die.

Selective: Only read Z die of your choice. Example: (3d6k1) = May choose 1 dice to keep from 3 thrown.

Count: See how many got over the check difficulty.

Highs And Lows: How many die went above the check difficulty = A. How many die went under the check difficulty = B. Example: (A - B) > 0, success (A - B) <= 0, failure

Check And Quality: First roll tells if you succeed. Second roll, gives quality. Example: d20 > check difficulty (skill modifier)d6, +1 quality for each 6.

Fudge Dice: Fudge dice is used in Fate systems.

d6 with three different sides: [-], [ ], [+] or 1-2, 3-4, 5-6

Each [+] boosts attempt quality, each [-] reduces attempt quality.

Quality Scale: Terrible, Poor, Mediocre, Fair, Good, Great, Superb

Dice notation is XdF where X is the number of fudge dice thrown. Example: 3dF


Each character has a hand of cards, depending on level. Each card has a suite e.g. strength, wisdom. You play these cards to checks and if right suite, you add top pile card also. You fill your hand. If you get damaged, you lose hand size and cards. You fill your hand after check.