Sources and method

Historical timezone offsets. This is what the whole site rests on: Peninsular Malaysia ran UTC+7:30 before 1982, UTC+9 under occupation 1941-45, and East Malaysia moved to +8 in 1933. We never hardcode an offset; we look up the one actually in force on the birth date.

Coordinates and timezone assignment for 519 cities. Longitude drives the true-solar-time correction. Licensed CC BY 4.0; this attribution is required by that licence.

Zi Wei Dou Shu star placement: the twelve palaces, fourteen main stars, auxiliary stars and brightness.

Lunar calendar conversion, the 24 solar terms, and the four pillars. Solar terms set the month pillar, so this feeds the BaZi directly.

9.87·sin(2B) − 7.53·cos(B) − 1.5·sin(B), where B = 2π(n−81)/365. A standard approximation, accurate to roughly half a minute. That error can only change the answer if a birth falls within about thirty seconds of a 时辰 boundary.

24.9% of Peninsular Malaysian births from 1946-1981 get the wrong main star (n=4000, sampled across three offset eras). This is the basis of the accuracy page.

A sweep of 51,840 charts. All forty-eight cells occur between 7.8% and 8.9% of the time, so no cell is a rare draw. This result is why the rarity badge we had planned was cut.

A sweep of 34,560 charts. Any formation matching more than a fifth of all charts is a rule written too loosely; that check removed three, one of which had been matching 58.9% of charts.

Lineages disagree on the 戊 and 庚 rows. We follow 中州派 and say so on the chart. The point is not that this lineage is right, but that you can see which one was used.

Stem 0.4, branch 0.6; a branch's hidden stems weighted 0.6 / 0.3 / 0.1. Relation adjustments: trine 0.15, half trine 0.07, harmony 0.08, punishment −0.08, with the total capped at 0.30. These ratios are a convention, not a measurement.

Main star 3.0, transformation 1.5, borrowed star 1.2, malefic 0.8, minor star 0.6. This is why that section shows a rank and a band and never the number: printing "13.7" would give these weights an authority they have not earned.

The published lists run to sixty or more. We implement the twenty-four whose rule can be stated exactly. Where lineages are vague, nothing is claimed rather than something guessed.

The Disruptor is not a literal translation of 破军; it is the rendering in common English use. 庚 is not a sword, it is yang Metal, and the sword is the image the tradition uses for it.

There are two methods for finding the 用神. We implement only 扶抑 (support-and-restrain), because it can be derived and checked. The other, 调候, reads the climate of the birth month — Wood born in winter needs Fire, Wood born in summer needs Water — and comes from 穷通宝鉴. The two sometimes disagree. We do not have that text, and reconstructing its hundred-and-twenty entries from memory is precisely what this site argues against.

For formations we check whether any of the six malefics falls across the Self triangle, because 無煞衝破 is an explicit classical condition. How malefics interact with each other, or are mitigated by auxiliary stars, is not modelled.

A clash is disturbance, not misfortune. Clashing a branch you needed is bad; clashing one working against you can be a release. The direction depends on a reading this engine does not have, and assigning a sign anyway would be dressing a coin flip as a calculation.

The decade and year ratings score whether a period's elemental character suits yours. They do not say what will happen. Identical birth details always produce identical output: this is a lookup, not a prophecy.