To cast an hexagram you will proceed as follows:

- Assign 2 to one side of each coin and 3 to the other one.
- Throw the three coins, sum the face values and draw the resulting line according the following table:

6 7 8 9 - Repeat step 2 other five times drawing the resulting lines from the bottom to the top of the hexagram.

This method is known to exist at least since the 7th century CE [1] or even a couple of centuries before [2]; it was popular during the T'ang dinasty. It's very easy and uses common objects that are easy to carry, no wonder it is still in so widespread use today.

Some criticized the usage of coins on the basis that the "true" method is the one using 50 yarrow stalks. Actually, this argument does not hold much as the original yarrows stalks method, which were in use around the year 200BC, is lost and what we have today is a reconstruction that dates around the year 1200CE [2].

Saying that using yarrow stalks (the way we know how to use them) is "truer" than using the coins has no much historical basis.

Others point out that since the assignment of the values to the faces is completely arbitrary, you could get the opposite hexagram instead of the "right" one. Personally I'm not so much worried about being "right" but I feel a little bit uneasy about the arbitrariety of the aassignement of values to faces. Actually this was one of the main reason for starting my search for an alternative casting methods that I felt more comfortable with.

If you prefer using chinese coins, as the ones in the picture, the side with four ideograms is usually considered 3. You can easily buy them online for a rather cheap price.

#### Probabilities

If we just consider the face that each coin can show after each throw, there are eight possible outcome:2+2+2 = 6 | |

2+2+3 = 7 | |

2+3+2 = 7 | |

3+2+2 = 7 | |

2+3+3 = 8 | |

3+2+3 = 8 | |

3+3+2 = 8 | |

3+3+3 = 9 |

Prob(6) = Prob(9) =

Prob(8) = Prob(7) =

Prob(

^{1}/_{8}= 12.5%Prob(8) = Prob(7) =

^{3}/_{8}= 37.5%Prob(

*yin*) = Prob(*yang*) =^{1}/_{2}This implies that the probability for a line to be a moving line is

^{1}/

_{4}, exatly as for the yarrow stalks method but getting a moving

*yin*line will be as frequent as getting a moving

*yang*line.

#### References

[1] Lars Bo Christensen, I Ching - The Original Core of the Book of Changes, 2015, http://zhouyi.dk/[2] Shih Chuan Chen,

*How to form a hexagram and consult the I Ching*, in

*Journal of the American Oriental Society*, 92.2 (1975), http://www.biroco.com/yijing/Shih-chuan_Chen.pdf

[3]

*How to consult the Yijing*, http://www.biroco.com/yijing/basics.htm

Coins image: https://commons.wikimedia.org/wiki/File:Ichingcoins.JPG

What a great site. Thank you for all info you put together.

ReplyDeleteAnybody have an opinion of whether heads is yin or yang? I seem to be finding both ways. Is one more traditional than the other? (I'm also assuming that "heads" refers to the inscribed side of the Chinse coin.)

ReplyDeleteThere's no general consensus on which side is which. I use coins very rarely but when I do, I decide the face values just before throwing the coins (of course, the association stay the same throughout the hexagram casting).

ReplyDeleteYou can check a rather long discussion on this topic here:

https://www.onlineclarity.co.uk/friends/index.php?threads/6-and-9-which-is-which-heads-2-or-3.8265/