Yellow–Black Path 黄黑道 Glossary

The twelve-spirit yellow/black day classification — a second, independent date-selection system that the classical literature explicitly says cannot be reconciled with Jian Chu.

Huang Hei Dao · 黃黑道 · 黄黑道 · huáng hēi dào · yellow path · black path · 黃道吉日

Source credibility (S/A/B/C/X): S    Rule computability (A/B/C): A

What it is

A day classification running through twelve spirits — six "yellow path" （黃道） and six "black path" （黑道） — computed from the day's combination of month branch and day branch. Folk practice calls yellow-path days auspicious; the label is a marker of the traditional system, not a prediction.

The important fact for anyone combining systems: the Xieji Bianfang Shu （協紀辨方書）, the Qing imperial compilation (1739, 36 juan), states the two systems cannot be made to agree — 「萬不能與建除相合」. Our almanac pages and API print that sentence next to the two side-by-side labels, and take no side.

School differences

Practitioners disagree about how to use the yellow/black labels together with the twelve officers; some traditions grade days by one, some by the other, some try to fuse them. The engine's position is methodological: compute both as transmitted, display both, refuse to merge them into a score.

How this engine computes it

• Computed from month branch (astronomical sectional term) and day branch (continuous cycle), as its own field — never folded into the officer field.
• Every almanac day prints officer + yellow/black label + the irreconcilability quote; the API returns both with the same caveat in disclaimer_note.
• Regression pins the flags against golden months in the test suite.

Related entries

Jian Chu · Six Officers (Liù Yào) · Solar Terms · School Dispute Register

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