I Ching simulator with accurate Yarrow Stalk probabilities

Details

External ID

46261942

Source

HN

Company

—

Product

I Ching simulator with accurate Yarrow Stalk probabilities

Website domain

castiching.com

Launched

Dec. 14, 2025

Cohort

—

Upvotes

63

Upvotes percentile

0.8454198473282443

Tags

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Fetched at

Sept. 7, 2026, 9:25 p.m.

Updated at

Sept. 7, 2026, 9:25 p.m.

Description

I built this because I wanted a digital I Ching that honors the original math, rather than just Math.random().Technical detail for the curious:The simulation follows the traditional Yarrow Stalk algorithm (Da Yan). The core of this algorithm relies on modulo-4 arithmetic on the stalks remaining after a random split.To make it physically realistic, I used a Box-Muller transform to simulate the user splitting the stalks with a Gaussian distribution (since humans naturally tend to split near the middle), rather than a uniform random split.I was worried this 'human bias' might skew the modulo probabilities, so I ran a 1-million-run Monte Carlo simulation to verify.The Result: The remainders [0,1,2,3] still emerged with a near-perfect 25% distribution (deviation < 0.05%).So, the app simulates the physics of human imperfection while preserving the mathematical perfection of the probability distribution (where Old Yin is 1/16).Stack: Next.js + Tailwind cssHappy to answer any questions about the math or the hexagrams!

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