Our method

Last updated: 2026-10-21

This English version is provided for convenience. If there is any inconsistency, the Traditional Chinese version prevails.

We believe transparency builds trust. Here is every step Xingban BaZi takes, from the details you enter to your Four Pillars.

1. The time you enter

You enter the local “clock time” at your place of birth. If you don’t know the time, we only calculate the year, month and day pillars (using noon internally for the day pillar) — we never guess your hour.

2. Hong Kong summer time

Between 1941 and 1979 Hong Kong used summer time (clocks one hour ahead) in many years. If you were born in Hong Kong on a date in the ranges below, we first subtract one hour to get Hong Kong Standard Time (UTC+8). Source: Hong Kong Observatory.

During the Japanese occupation (1942–1945) Tokyo time (UTC+9) was used, which the Observatory lists as year-round summer time, so we also subtract one hour. The exact switch-over moment on changeover days isn’t always fully recorded; if you were born on one, your result page will let you know.

• 1941-06-15 to 1941-09-30
• 1942-01-01 to 1945-12-31
• 1946-04-20 to 1946-12-01
• 1947-04-13 to 1947-11-30
• 1948-05-02 to 1948-10-31
• 1949-04-03 to 1949-10-30
• 1950-04-02 to 1950-10-29
• 1951-04-01 to 1951-10-28
• 1952-04-06 to 1952-11-02
• 1953-04-05 to 1953-11-01
• 1954-03-21 to 1954-10-31
• 1955-03-20 to 1955-11-06
• 1956-03-18 to 1956-11-04
• 1957-03-24 to 1957-11-03
• 1958-03-23 to 1958-11-02
• 1959-03-22 to 1959-11-01
• 1960-03-20 to 1960-11-06
• 1961-03-19 to 1961-11-05
• 1962-03-18 to 1962-11-04
• 1963-03-24 to 1963-11-03
• 1964-03-22 to 1964-11-01
• 1965-04-18 to 1965-10-17
• 1966-04-17 to 1966-10-16
• 1967-04-16 to 1967-10-22
• 1968-04-21 to 1968-10-20
• 1969-04-20 to 1969-10-19
• 1970-04-19 to 1970-10-18
• 1971-04-18 to 1971-10-17
• 1972-04-16 to 1972-10-22
• 1973-04-22 to 1973-10-21
• 1973-12-30 to 1974-10-20
• 1975-04-20 to 1975-10-19
• 1976-04-18 to 1976-10-17
• 1979-05-13 to 1979-10-21

There was no summer time in 1977, 1978 or from 1980 onwards. If you were born outside Hong Kong, you can choose a city or enter the longitude and time zone yourself, and tick whether daylight saving time was in effect.

3. True solar time

Traditional BaZi uses the sun’s position to define the hour. We convert in two steps:

• Longitude correction: every degree of longitude is 4 minutes. Hong Kong is about 114.17°E, west of the 120° time-zone meridian, so roughly 23 minutes are subtracted. We use the longitude of the district or city you choose.
• Equation of time: because Earth’s orbit is elliptical, the sun runs “fast” or “slow” by about −14 to +16 minutes over the year. We calculate this for your date with a standard approximation (accurate to about ±1 minute).

4. How the Four Pillars are set

• Year pillar: begins at Lichun (立春, the Start of Spring), not Chinese New Year.
• Month pillar: changes at the twelve “Jie” solar terms (立春, 驚蟄, 清明…). Year and month pillars compare your exact moment of birth with the solar-term times.
• Day and hour pillars: calculated from true solar time at your birthplace. We change the day at 23:00 (the start of the Zi hour).
• Calendar calculations use the open-source lunar-javascript library (Shouxing astronomical algorithms), cross-checked against a second, independent calendar library.

5. Ten Gods, Five Elements and Luck Pillars

• Ten Gods (十神): with your Day Stem as “you”, the other stems and hidden stems are classified by Five-Element production/control and yin/yang.
• Five Elements balance: each heavenly stem counts 1; each earthly branch counts its hidden stems as main 1, middle 0.5 and residual 0.3; the month branch (season) counts double. We also show the visible character count.
• Day Master strength (simplified): the share of same-element (Companion) and supporting (Resource) energy in the total — 52% or more is strong-leaning, 40% or less is soft-leaning, anything between is balanced. This is a simplified assessment, not a full structural analysis.
• Luck Pillars (大運): run forward for yang-year men and yin-year women, and in reverse for yin-year men and yang-year women; the starting age is based on the distance from birth to the previous or next “Jie” term (three days = one year).

6. How reports are written

Reports are generated by rules: your Day Master, Ten God combinations, Spouse Palace, Five-Element balance, annual and Luck Pillars are matched to gentle, pre-written interpretations. The English edition has its own hand-written library of interpretations rather than a word-for-word machine translation, and BaZi terms keep their Chinese name with a short gloss. If AI wording polish is enabled (Traditional Chinese only), the AI may only adjust tone — it cannot change any stems, branches, years or numbers, or add scary or guaranteeing language.

7. What we never do

• Claim an “accuracy rate” or guarantee any outcome
• Scare you into paying with talk of “bad luck” or disaster
• Use made-up masters or fake reviews