What coins should you use for the I Ching?

You can use any three coins for an I Ching reading. Traditional Chinese cash coins, round with a square hole, are the classic choice and many people enjoy them, but the method only needs two distinguishable faces and a rule, fixed in advance, for which face counts 3 and which counts 2. Nothing about the metal, the age or the price of the coins changes the odds or the meaning of the result.

What the method actually needs

The three-coin method turns each throw into a number: one face of each coin counts 3, the other 2, and the total of three coins is 6, 7, 8 or 9. For that to work you need only:

• Three coins (or one coin thrown three times — the odds are the same).
• Two faces you can tell apart at a glance, so you never hesitate over a reading.
• A rule for which face is 3, decided before you toss and kept for good. The traditional rule, which this site follows, is explained in which side of the coin is yang.
• Coins that are reasonably fair. A badly bent or very lopsided coin could in principle favour one face; ordinary coins in normal condition are close enough.

That is the whole technical requirement. Everything else is about how the practice feels to you.

Chinese cash coins

The coin most associated with the I Ching is the Chinese cash coin (方孔圓錢): a round coin with a square hole in the middle, cast in bronze for more than two thousand years. The shape is often explained as round heaven enclosing square earth (天圓地方), a pleasing image for a book about heaven and earth, though the hole also had the practical job of letting coins be strung together.

Some types you will come across:

• Kaiyuan Tongbao (開元通寶), first cast under the Tang in 621, one of the longest-circulating coin types in Chinese history.
• Qing-dynasty coins with a reign title on the front, such as 康熙通寶 or 乾隆通寶. Their reverse usually carries a mint name in Manchu script, so the "plain" side (背) is not actually blank; it is simply the side without the four Chinese characters.
• "Five emperors" sets (五帝錢), coins of the first five Qing reigns sold together, popular in feng shui. For divination you only need three of them.

Almost all cash coins sold today for divination are modern castings, not antiques. That is perfectly fine. If you do own genuine old coins, there is no need to clean or polish them for use; a gentle wipe is enough, and many collectors would rather you left the patina alone.

The real advantage of cash coins is clarity. One side has four large characters and the other does not, so you never confuse the faces, and the traditional rule (inscribed side 2, reverse side 3) applies directly.

Ordinary coins

Ordinary modern coins work just as well. The only task is deciding which face is which:

• Choose three coins of the same type, so every coin follows the same rule.
• Decide whether heads or tails counts 3. If you want to match the traditional convention, treat the side with more text as the inscribed side, worth 2.
• If the faces look alike, mark one side of each coin with a small dot of paint or a sticker and note in your journal what the dot means.

Some readers like to set aside three particular coins, perhaps from a meaningful year or place, and use them only for readings. That is a personal touch, not a requirement.

Care and ritual

The tradition does attach importance to how you consult. Zhu Xi's short divination ritual (筮儀), printed at the front of his Original Meaning of the Zhouyi, describes a quiet, clean room, a table, incense and a respectful manner — for the yarrow-stalk method, which takes far longer than coins. Many coin users adapt a little of this:

• Keep the coins in a small pouch or box, used only for readings.
• Clear a space, sit down, and write the question before you touch the coins.
• Hold the coins in cupped hands, or shake them in a small shell or cup, while you keep the question in mind; Six Lines practitioners often use a tortoise shell for this.
• Throw onto a soft surface so the coins do not roll away.

None of this is magic. What it does is slow you down. The Judgment of Hexagram 4, Meng warns that asking "again and again" is importunate (再三瀆), and a small, deliberate routine is the easiest way to make each cast a single serious question rather than one of a hurried series. Confucian tradition put the underlying quality in a word, sincerity (誠); the Doctrine of the Mean goes as far as 至誠之道，可以前知, "the way of utmost sincerity can know beforehand". Whatever you make of that claim, the attitude it recommends is a good one to bring to a reading.

Common worries

• Do the coins need to be consecrated or cleansed? The classical sources ask for no such thing. Zhu Xi's ritual is about a clean place and a respectful attitude, not about treating the objects. A wipe and a fixed resting place are a fine way to mark the coins as special; skipping them changes nothing.
• Can you use borrowed or second-hand coins? Yes. A coin is a way of producing a random number; it does not carry anyone else's question.
• Does the denomination or age matter? No. Large or small, new or worn, a coin in this method is simply two faces.

Does any of it change the result?

On the numbers, no. Antique or modern, bronze or nickel, three coins or one thrown three times: each line still has a one-in-eight chance of being old yin, three in eight of young yang, three in eight of young yin and one in eight of old yang. The 64 hexagrams and their texts are the same whatever you toss.

Nor is a digital cast inferior in this respect. On the I Ching page the server tosses three virtual coins per line with a cryptographic random source, using the same values. The comparison of online and physical casting looks at the difference fairly: it lies in the experience, not the probabilities. And if you would rather not toss anything at all, the Plum Blossom method builds a hexagram from numbers or the time.

Getting started with your coins

• Pick three coins you can tell apart at a glance and fix your rule for which face is 3.
• Write the question down first, then throw six times, recording each total from the bottom line up.
• Build the hexagram, look it up in the hexagram library, and read any moving lines by the changing-line rules.
• Put the coins away when you are done. One question, one cast.