Da Yan Shi Fa (大衍筮法) — I Ching Yarrow Stalk Oracle

The I Ching states: 'The number of the great expansion is fifty, of which forty-nine are used (大衍之数五十，其用四十有九).' The number 50 represents the totality of cosmic transformation. One stalk is set aside to symbolize Tai Ji — the Supreme Ultimate from which all things originate. The remaining 49 stalks produce specific probability distributions through the dividing and counting process: old yang (1/16), old yin (3/16), young yang (5/16), young yin (7/16), reflecting the I Ching's core principle of yang-yin asymmetry.

Da Yan Shi Fa is the original divination method recorded in the I Ching, while the coin method is a later simplification. The key difference lies in probability: in Da Yan Shi Fa, old yang has 1/16 probability and old yin 3/16, but in the coin method both have 1/8. This means changing lines appear with different frequency and asymmetry in the yarrow stalk method, better reflecting the I Ching principle that 'yang moves, yin rests.' Additionally, the eighteen-change process (three changes per line × six lines) serves as a meditative ritual emphasizing sincerity.

Changing lines occur when a line is old yin (6) or old yang (9) — it transforms into its opposite, creating a changed hexagram. Interpretation rules: no changing lines — read the primary hexagram judgment; one changing line — read that line's text; two changing lines — emphasize the upper one; three changing lines — compare both hexagram judgments (primary = inner truth, changed = outer direction); four changing lines — read the two unchanged lines in the changed hexagram; five — read the single unchanged line; all six change — for Qian/Kun use the special 'all nines/sixes' text, otherwise use the changed hexagram judgment.

The mathematics are identical — our implementation strictly follows the algorithm described in the Xi Ci Zhuan (Commentary on the Appended Judgments). The random division model is mathematically equivalent to physical stalk division. The difference is experiential: real stalks have tactile and ritual qualities. Our hands-on mode recreates this as closely as possible, letting you personally perform each step of dividing, setting aside, counting by fours, and collecting remainders.

Da Yan Shi Fa originates from the I Ching's Xi Ci Zhuan (c. 800 BCE) and is the oldest orthodox divination method, requiring eighteen changes to complete one hexagram. Plum Blossom Numerology was created by Shao Yong (1011-1077) during the Song Dynasty and uses numbers, time, directions, or spontaneous observations for quick hexagram generation. Both are rooted in I Ching philosophy, but Da Yan Shi Fa emphasizes ritual precision and mathematical derivation, while Plum Blossom emphasizes symbolic association and intuitive insight.

Traditionally, the division is done randomly without deliberately aiming for any specific ratio. This randomness is what gives divination its element of uncertainty, which the ancients regarded as the manifestation of heaven's will. Mathematically, different divisions affect the subsequent counting remainders and thus the final line result. In our simulator, the manual mode allows you to freely drag the divider, fully recreating this process.

'Set one aside to symbolize the three powers (挂一以象三)' — one stalk is taken from the right pile (Earth) and held between the fingers of the left hand, symbolizing Humanity. This way, the left hand holds Heaven's stalks, the right hand holds Earth's stalks, and one stalk between the fingers represents Humanity — together forming the 'Three Powers' (天地人三才). This is the core philosophy: any divination must consider the three dimensions of Heaven, Earth, and Humanity. After setting one aside, the right pile decreases by one, and 48 stalks actually participate in counting.

Counting by fours means taking stalks from a pile four at a time until 1-4 remain — this remainder is the counting result for that pile. The same is done for the other pile. Groups of four symbolize the four seasons. The left remainder plus the right remainder plus the one set aside always totals either 5 or 9 (first change), or 4 or 8 (second and third changes). This mathematical constraint is what produces the specific probability distribution of the four line types.

'Collecting the remainders' means gathering the counting remainders and placing them aside. 'Qi (奇)' means remainder, and 'Le (扐)' refers to stalks held between fingers. After each change, the left remainder, right remainder, and the one set aside are combined and placed to the side. The remaining stalks are used for the next change. After three changes, the nature of the line is determined by the remainder values (5 or 9, 4 or 8) from each change.

After each change, divide the collected remainder by 4: 5÷4≈1 counts as 1, 9÷4≈2 counts as 2, 4÷4=1 counts as 1, 8÷4=2 counts as 2. Add the three values: three 1s = 3 (old yang, changing ⚊), two 1s + one 2 = 4 (young yin ⚋), one 1 + two 2s = 5 (young yang ⚊), three 2s = 6 (old yin, changing ⚋). Alternatively, subtract the total remainders from 49 and divide by 4: 6 = old yin, 7 = young yang, 8 = young yin, 9 = old yang.

The soul of Da Yan Shi Fa lies in the process, not merely the result. One-click auto divination simply generates a set of random numbers in an instant, completely disconnecting the diviner from the process. With hands-on operation, you personally perform every step — dividing, setting aside, counting by fours, and collecting remainders — exactly as described in the Xi Ci Zhuan. From a traditional I Ching perspective, the diviner's intention, focus, and sincerity are infused into the arrangement of stalks through the hands — this is the essence of 'sincerity brings efficacy.' The eighteen changes are not meaningless waiting; they are a complete experience of dialogue with Heaven and Earth. Auto mode is suitable for learning the process, but when you truly have something to consult, hands-on operation is the only way to fully embody the spirit of Da Yan Shi Fa.

In manual mode, every action you take directly determines the hexagram's trajectory. The position where you drag the divider determines the number of stalks in each pile, directly affecting subsequent counting remainders. The remainders after counting by fours (1-4 stalks) determine each change's result. The combination of three change results ultimately determines whether a line is old yang (9), young yang (7), young yin (8), or old yin (6). Across six lines and eighteen changes, you make 18 critical choices by hand. This is mathematically identical to real yarrow stalk operation — the randomness of each division comes from you, not from a computer's pseudo-random number generator. In other words, the hexagram is 'produced by your hands,' not 'calculated by a machine.'

A complete manual Da Yan Shi Fa session requires eighteen changes, each involving four steps: dividing, setting aside, counting, and collecting. The entire process takes approximately 15-30 minutes. During this time, you must maintain focus — even a moment's distraction can lead to operational errors. This enforced concentration has a meditation-like effect: external distractions gradually fade, the mind returns to calm, and thoughts focus on the matter being consulted. The ancient requirement to 'fast, bathe, burn incense, and cleanse the hands' before divination was essentially about creating this state of focused reverence. In today's fast-paced life, hands-on Da Yan Shi Fa offers a rare opportunity to 'slow down,' finding inner peace and clarity through ritual.

The vast majority of online divination tools only offer one-click result generation, reducing Da Yan Shi Fa to a random number function — this discards its most essential value. What's lost isn't just ritual atmosphere, but the deep connection between diviner and hexagram. This tool's manual mode is one of very few online implementations that fully recreate the complete Da Yan Shi Fa process: you can drag the divider to simulate the random splitting, click to take one stalk simulating setting aside, observe the counting-by-fours process, and confirm collection results. Every step features intuitive visual feedback and operation guidance, preserving the solemnity of traditional ritual while lowering the learning barrier. For modern practitioners who cannot obtain real yarrow stalks, this is the closest experience to the ancient method available.

Modern psychological research shows that humans have stronger identification with and trust in results they personally helped create — known as the 'IKEA Effect' and the 'need for perceived control.' When you personally operate each step of Da Yan Shi Fa, the hexagram is no longer a cold random output but a result you deeply participated in, investing your full attention. This sense of participation makes you more willing to seriously consider the hexagram text's meaning and engage in deep self-reflection. Additionally, the 15-30 minute operation process functions as 'structured meditation,' helping you break free from daily thinking patterns to examine problems from entirely new perspectives. Jung's 'synchronicity' theory also suggests that when a person is in a state of high focus and openness, they are more likely to perceive meaningful coincidences. Hands-on operation is the optimal way to enter this state.

Hands-on operation is the most effective way to learn Da Yan Shi Fa, offering irreplaceable educational value: 1) Deep Understanding of Principles — Only by personally experiencing dividing, setting aside, counting by fours, and collecting remainders can you truly grasp every phrase in the Xi Ci Zhuan; 2) Mastering the Mathematical Model — Through repeated operation, you'll intuitively understand why the first change yields only 5 or 9, and the second and third only 4 or 8; 3) Memorizing the Six-Line Process — Hand-brain coordination enhances memory retention exponentially compared to passive observation; 4) Cultivating Practical Skills — Many learners know hexagrams but can't actually divine; manual mode fills this gap. Our tool provides complete step-by-step guidance and visual feedback, enabling even complete beginners to quickly master the technique.

Da Yan Shi Fa represents 5,000 years of Chinese civilization's crystallized wisdom. Hands-on operation carries profound significance for cultural preservation: 1) Protecting Intangible Cultural Heritage — As China's most orthodox ancient divination method, its complete ritual process faces the risk of being lost; online manual mode becomes a crucial means of transmission; 2) Living Transmission — Hands-on operation brings the ancient method 'to life,' allowing modern people to experience ancestral wisdom firsthand; 3) Cultural Identity — Completing the eighteen changes fosters deep appreciation of ancient Chinese mathematics and philosophy; 4) Educational Dissemination — Manual mode lowers learning barriers for younger generations; 5) International Communication — Online manual simulation provides a vivid vehicle for showcasing Chinese civilization to the world.