Two dice (2d12)

You can mark two twelve sided dice to make them able to cast lines with the yarrow stalks probabilities.

One of the dice has:

• Three faces with 3 dots
• All the other faces with 4 dots.

The other dice has:

• Three faces with 3 dots
• Three faces with 5 dots
• All the other faces with 4 dots.

To cast a line you just cast the two dice together and sum the dots.

You'll get 6,7,8 or 9 with yarrow stalks probabilites:

Probabilities

The table on the right shows all the possible combinations for the two dice. Counting the number of 6,7,8 and 9 it's easy to see that:

Prob(6) = ⁹/₁₄₄ = ¹/₁₆
Prob(8) = ⁶³/₁₄₄ = ⁷/₁₆
Prob(7) = ⁴⁵/₁₄₄ = ⁵/₁₆
Prob(9) = ²⁷/₁₄₄ = ³/₁₆
Prob(yin) = Prob(yang) = ¹/₂

Variations

To get lines with 3 coins probability, mark the first dice as follows:

• Six faces with 3 dots
• Six faces with 4 dots 

 

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Spinning dice

 

The picture on the left is the 3D reconstruction of a simple device I made long time ago. Unfortunately I lost it and never made another one, so I created this 3D model to show how it worked.

To make one yourself, take two dice, drill a hole in both and make them turn freely around a stick (or a cord).

Mark the left die faces with 3,4,4,4 dots and the right die faces with 3,4,4,5 dots.

To cast a line, spin the two dice in opposite directions for as long as you feel appropriate and when you stop them, add the dots. You'll get 6, 7, 8 or 9 with yarrow stalks probabilities.

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Eight cards

 Yes, I came up with another cards design!

This time it's for 8 proper cards. With proper I mean that the back has a geometric pattern while the front of each card has a different design:

and here is the cards back:

Each card represents one of the eight trigram with, enclosed in the square, its name in red.

At the corners you'll find, in black, a chinese numeral (6,7,8 or 9) and, in red, the associated image (heaven, fire, wind, ...).

Should you, like me, have troubles remembering traditional chinese numerals, below them there are some black dots. Just add six to the number of dots in the corner and you'll get the numeral value.

Using these cards you can cast lines with yarrow stalks probabilites as follows:

• Shuffle the eight cards, mix them and rotate at will.
• Pick a card and rotate it again until you feel satisfied.
• Flip the card and look at the upper left corner (do not change the orientation of the card, being upside down or not is part of the casting process). 
• Use the chinese numeral (or the number of dots) to determine the line according to the following table:
  

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