V. From Yarrow Stalks to Bronze Coins: The Decline and Evolution of Divination Methods

The Great Expansion Milfoil Method flourished from the Shang and Zhou dynasties through the Han. However, as the wheel of history turned, it was gradually marginalized.

1. Complexity Is the Greatest Adversary

Completing a single proper Great Expansion divination takes a swift practitioner fifteen to twenty minutes, and a slower one up to half an hour. Moreover, it is exceedingly easy to miscount during the process — one error and the entire result is invalidated. For the battlefield demanding urgent decisions or the marketplace diviner serving common folk, this was simply too slow.

Thus, from the Tang and Song dynasties onward, the "Fire Pearl Forest Method" (Huo Zhu Lin Fa — the coin method, also known as Six-Line Najia divination) rose to prominence. One need only shake three bronze coins six times, and a hexagram can be formed in a matter of minutes. Moreover, the Five Phases mutual generation and conquest system became more standardized and easier to learn.

2. The Price of "Sincerity of Heart"

The Great Expansion Milfoil Method emphasizes ritual gravity and the attainment of "unity between Heaven and Man" through the prolonged process of counting yarrow stalks. As divination gradually became secularized and commercialized in later periods, people grew more concerned with the accuracy of results than with the psychological cultivation inherent in the process of seeking a hexagram.

3. A Modern Perspective: Why We Still Need the Great Expansion

In an age when computer algorithms can generate hundreds of millions of random numbers in a single second, does the Great Expansion Milfoil Method retain any significance$3 The answer is emphatically yes.

• The wisdom of slowness: In this age of acceleration, the Great Expansion Milfoil Method compels us to slow down. The dividing and recombining of those forty-nine yarrow stalks is, in truth, a process of ordering one's thoughts. By the time you have completed the eighteen transformations, perhaps even before the hexagram appears, the answer already resides within your heart.
• A simulation of chaos theory: As discussed above, the distinctive probability distribution of the Great Expansion Milfoil Method constitutes an ancient simulation of nature's "nonlinear systems." It reminds us that the world's development tends toward inertia (Young Yang, Young Yin), while sudden transformations (Old Yang, Old Yin), though crucial, are rare occurrences.