Yin/Yang - Variance Dice

In general I follow the concept of wherever possible decisions should drive action resolution. However when it gets right down to it you have to admit the world is never quite so cut and dried... it is torn and fluid. Variance Dice also called Yin Yang Dice add variation to your effective ability and they represent the variations in performance and results that are derived of minutia we cannot really track.

One of the fun parts of YinY ang Dice is that long time players can dig out their dice bags and feel how cool it is to have an innovative use for all those various sized and colored dice. ;-) Yin Yang dice are rolled in duo colored pairs.   Add the white die and and subtract the black die (actually any two consistent distinct colors can be used) from your affective ability in performing the action, your resultant ability is then compared to the difficulty threshold of the action normally.

If the action is actively opposed whoever is playing the adversary should roll variance dice and modify the actions difficulty based on them.  Passively opposed actions can be seen as having a predetermined static difficulty.

(DOS) Degree of Success... Ability minus Difficulty
(DOF) Degree of Failure... Difficulty minus Ability

So called critical success and critical failures are merely extremes in the range of degree of success of failure and not artificially imposed. 

What number and size of dice can be used for Yin/Yang Dice?

Why any size and number could work sort of it is a part of the beauty of it.  By controlling the size and number of variance dice you can control how extreme the results can be and how much of a bell curve you get all independent of what the average result is. 

The size and number of pairs of dice can be customized to what rating system you use for abilities.   So folk with abilities averaging 6 might have a desired variance of say +/- 3 this is easily done by a single pair of 4 sided Yin Yang dice for instance. The label for this is 1Y4 or just Y4, Yin Yang dice are numbered according to the number of pairs and size not the number of individual dice.

Obviously there are really only a small number of polyhedrons/convenient methods that can be used for actually doing variance dice some would need be specially constructed by labeling. Y2,Y3.Y4,Y5,Y6,Y8,Y10,Y12,Y20,Y30

Varying the Variance

Modifying the size of the YinYang dice based on the riskiness of maneuvers is a very elegant method of implementing Risk in a game using dice.

More extreme and  stressful circumstances and actions can slide the variance up, increasing the size of dice where as cautious choices and certainty reduce them.  In the example above we could rule combat increases the basic pair size to Y5 (oddly labeled 10 sided dice)

Individuals with higher skills usually use lower performance variance hence smaller sized Yin Yang dice as do characters behaving cautiously.    More exacting and precise skill seems to "cause" less variable performance even in circumstances that normally would be stressful .  The repetitive exercise that provides and promotes skill (and a higher mean performance) also inhibits wildness and variation in performance.  There is a strong  tendency to do things the same way the more you have done them, even when you are feeling challenged and should probably improvise a little more.  "Soldiers" might usually chose smaller YY  than "Heroes".  A character with advanced skill in combat behaving cautiously could be ruled to have  Y3.   

In the spirit of decision driven gaming it seems very reasonable to allow the player( or Story guide for NPCs') within bounds to directly select the size of the variance dice his character rolls [ The story guide may actively modify this if necessary within ranges of circumstance can increase or decrease the range of dice sizes he/she can choose from. )

An actions wildness and potential for inspired or terrible results should be based on various factors should be reflected in the dice size employed. Things to consider when deciding this.

• Perceived Need and Relative Ability versus action Difficulty : The essential determinant over whether a circumstance is "stressful"  and also whether extreme results are needed is in the hands of the characters own perceptions.  A character doesn't necessarily know what the "true" performance difficulty is when they attempt many actions, they may have a guess for well known skills it may even be a very good guess especially if  they have perception skills geared just for it such as a specific analyze adversary the accuracy of their guesses can be used to help decide on the dice size, they use as well as a method to decide if the better part of valor is called for.  A skilled character effectively needs less variance to accomplish his goals and can afford to  take fewer chances.
• Description of the Action:
  Vivid terminology can help determine how extreme the move is intended to be.  The description needs to be appropriate for the dice used and vice versi one should be based on the other... your choice.
• Strategic Element  of the Action:
  Generally speaking direct maneuvers tend to be more aggressive (risky) and responsive ones more cautious. Offensive moves are of course normally more risky( last moment defenses are a way to throw your opponent off their mark.)
• Nature of Character:
  A Characters defined style can implicitly affect their tendency to be risky or cautious, such style might be a function of the school at which they were taught or simply a personality feature, and might even be specific to the type of conflict they are engaged in.
• Additional Situational Elements  many possibilities such as  being in a rush can and should be considered. Using active Magick to enhance your combat abilities could be able to increase variance dice sizes beyond normal extremes

The story guide should feel free to limit dice size choices he allows a character for instance the greater sized YY dice only be available to those with extraordinary features 

For instance:  Active use of wild chaos magic may be one of the few ways of achieving a Y30. and may require a minimum of D12.

More Coming Hopefully Clearer examples ;)