蓍草占法：最古老的易经起卦方法

蓍草占法的历史渊源

蓍草占法（也称"大衍之数法"或"揲蓍法"）是《周易》记载的最古老、最正式的起卦方法。其理论根据出自《周易·系辞传》：

"大衍之数五十，其用四十有九。分而为二以象两，挂一以象三，揲之以四以象四时，归奇于扐以象闰。五岁再闰，故再扐而后挂。"

这段话精炼地描述了蓍草占法的核心操作，每一步都对应着天地自然的运行法则——分二象两仪，挂一象三才，揲四象四时，归奇象闰月。蓍草占法不仅仅是一种随机取数的手段，更是一场人与天地沟通的仪式。

Historical Significance

The yarrow stalk method is the original divination technique described in the Xi Ci Zhuan (Commentary on the Appended Judgments), one of the Ten Wings of the I Ching. For over two thousand years, this was the standard method used by court diviners and Confucian scholars.

The yarrow plant (Achillea millefolium) was chosen for its symbolic significance. Ancient Chinese believed that yarrow grew abundantly around the graves of sages, and that the plant itself possessed a spiritual quality that made it suitable as a medium between human inquiry and cosmic wisdom. The Xi Ci Zhuan states: "蓍之德，圆而神" — "The virtue of the yarrow is round and spiritual."

The method fell out of common use after the Three Coins method gained popularity during the Song dynasty (960-1279 CE) for its simplicity. However, many serious I Ching practitioners continue to regard the yarrow stalk method as the more authentic and spiritually complete approach.

完整流程：四营十八变

蓍草占法的完整过程称为"十八变"，即经过十八次操作得到一个完整的六爻卦。每三变得一爻，因此六爻共需十八变。每一变的过程称为一"营"，三营构成一爻，故也称"四营十八变"（四营指分二、挂一、揲四、归奇四个步骤）。

准备工作

取蓍草50根（传统用干燥的蓍草茎，现代可用竹签或木棍代替）。先取出1根放置一旁，此根自始至终不参与运算，代表太极之体——"其用四十有九"。

第一变

步骤一：分二（象两仪）

将49根蓍草随机分为左右两组，分别代表天与地、阳与阴。

步骤二：挂一（象三才）

从右手一组中取出1根，夹在左手小指间。这1根代表"人"，与天地合为三才。

步骤三：揲四（象四时）

将左手一组每4根一数（象征春夏秋冬四时），记录余数。然后将右手一组也每4根一数，记录余数。

步骤四：归奇（象闰月）

将两次揲四的余数与挂一的那1根合在一起放置一旁。余数可能为4或8根。

第一变完成后，剩余蓍草数为44或40根。

第二变

将第一变剩余的蓍草重新合在一起，重复分二、挂一、揲四、归奇的过程。这一次不再从50根开始，而是用上一变剩余的蓍草数。第二变归奇的余数可能为4或8根。

第三变

将第二变剩余的蓍草再次重复上述过程。第三变归奇后，最终剩余的蓍草数除以4，得到的商即为本爻的数值：

• 商为6：老阴（变爻）——记为 ▅▅ ▅▅ ×
• 商为7：少阳（不变）——记为 ▅▅▅▅▅
• 商为8：少阴（不变）——记为 ▅▅ ▅▅
• 商为9：老阳（变爻）——记为 ▅▅▅▅▅ ○

重复六次

从初爻（底部）到上爻（顶部），依次完成六个爻的十八变过程，即得到一个完整的六爻卦。

如需在线体验蓍草占法的完整过程，可使用我们的蓍草占卜工具。

概率分析：蓍草法 vs 三枚铜钱法

蓍草法与三枚铜钱法在概率分布上存在显著差异，这是许多传统派学者坚持使用蓍草法的重要原因。

Three Coins Method Probabilities

The three-coin method produces each line through a single toss of three coins. The probabilities are straightforward:

This means changing lines appear 37.5% of the time (25% + 12.5%), and notably, Old Yin (6) is twice as likely as Old Yang (9).

Yarrow Stalk Method Probabilities

The yarrow stalk method produces a markedly different distribution:

Here changing lines appear only 25% of the time (6.25% + 18.75%), and Old Yang (9) is three times as likely as Old Yin (6).

概率差异的意义

这两种概率分布反映了不同的宇宙观假设：

蓍草法的特点：

• 变爻出现概率较低（25%），意味着卦象更稳定，变卦较少出现
• 老阳（9）的概率是老阴（6）的三倍，体现了"阳主动、阴主静"的哲学——阳爻更容易发动变化
• 阴爻总体概率（50%）略高于阳爻（50%），但阳爻的"动能"更强

三枚铜钱法的特点：

• 变爻出现概率较高（37.5%），卦象变化更频繁
• 老阴（6）的概率反而是老阳（9）的两倍，这与传统哲学中"阳动阴静"的观念相矛盾
• 概率分布的对称性更强，但缺乏蓍草法内蕴的阴阳动静之理

许多易学研究者认为，蓍草法的概率分布更符合《周易》原本的设计意图。南宋朱熹在《周易本义》中详细记述了蓍草占法的步骤，并以此作为正统方法。

Why the Probabilities Differ

The mathematical difference arises from the structure of the yarrow stalk process itself. In the three-coin method, each toss is a simple independent event with symmetric probabilities. In the yarrow stalk method, the three successive divisions are dependent operations — the result of the first division constrains the possible outcomes of the second and third divisions.

Specifically, the first division can produce a remainder of either 4 or 8, but these are not equally likely. The probability of getting a remainder of 4 in the first division is 3/4 (since there are three ways to get a remainder of 1, 2, or 3 from the left pile, plus the hung stalk). This asymmetry cascades through the subsequent divisions, producing the characteristic 1:5:7:3 ratio.

This mathematical elegance is one reason many scholars view the yarrow stalk method as a more sophisticated system — the dependent operations create a probability structure that mirrors the I Ching's philosophical emphasis on the dynamic interplay between yin and yang.

现代实践指南

材料准备

现代实践者通常使用以下替代材料：

• 竹签或木棍：最常见的替代品，长度约25-30厘米
• 筷子：取50根一次性竹筷也可使用
• 专用蓍草签：一些易学用品店出售仿制蓍草签

仪式建议

传统蓍草占法重视仪式感，这并非迷信，而是帮助求测者进入专注、虔诚的心理状态：

1. 选择安静的环境，关闭手机等干扰源
2. 净手焚香（可选），传统认为有助于"通神明之德"
3. 默念所问之事，心中保持诚敬
4. 操作时保持专注，将每一步视为与天地沟通的过程
5. 记录完整过程，包括日期、时间、所问之事、每一变的数据

时间预估

完整的蓍草占法需要20-30分钟。相比三枚铜钱法的2-3分钟，时间投入显著增加。但支持者认为，这种"慢"恰恰是其价值所在——缓慢的过程本身就是一种冥想，帮助求测者沉淀心神、与卦象建立更深层的连接。

Choosing Your Method

For beginners, the three-coin method offers an accessible entry point to I Ching divination. Its simplicity allows you to focus on learning interpretation rather than procedure. As your practice deepens, consider experimenting with the yarrow stalk method to experience the fuller ceremonial dimension of the I Ching tradition.

Neither method is "wrong." The three-coin method has been used effectively for centuries and has its own historical legitimacy. However, if you value mathematical authenticity to the original Xi Ci Zhuan description, philosophical alignment with yin-yang dynamics, and the meditative quality of a longer ritual process, the yarrow stalk method is worth the additional effort.

了解更多起卦方法的对比，请参阅起卦方法总览。无论选择哪种方法，关键在于以诚心正意面对每一次占卜，让卦象成为自我反思与生命探索的工具。