askjoss
Methods

How we calculate

Everything runs in your browser from open, deterministic code. Same inputs, same answer, every time.

Calendar and time

  • Solar terms come from a truncated VSOP87 solar model with nutation, aberration and ΔT. Checked against published tables to within two minutes for 2020–2030.
  • True solar time: your clock time is converted to UTC using your birth city's time-zone history (including daylight saving), then shifted by longitude and the equation of time.
  • Year changes at the exact moment of Lichun (Start of Spring), not on January 1 or Lunar New Year. Months change at each of the twelve "jie" solar terms. A birth after 23:00 counts as the next day (early Zi hour convention).

Joss Profile (BaZi)

  • Four pillars, ten-god roles of every stem and hidden stem.
  • Element balance counts each visible stem as 1 and each branch's hidden stems as 1, or 0.7/0.3, or 0.6/0.3/0.1.
  • Day Master strength is a 0–100 score: season (up to 40), roots in the branches (up to 25), resource stems (up to 20) and peer stems (up to 20). 45 or more counts as strong.
  • Favorable elements follow simplified strength-balance (扶抑) rules. We do not model seasonal adjustment (調候), bridging elements, follow or transformation structures, or combinations. A master may disagree in edge cases, and we say so.
  • Ten-year luck cycles run forward for yang-year men and yin-year women, backward otherwise; the starting age is the days to the nearest solar term ÷ 3.

Daily Joss (Tong Shu)

  • Day officer (建除), yellow/black path spirits, lucky hours, lunar mansion and directions follow standard almanac tables, checked against printed almanacs.
  • The good-for / avoid lists use a simplified table keyed on the day officer. Printed almanacs weigh many more spirits. We show ours as a guide, not a full almanac.
  • Your personal rating compares the day with your Day and Year branches (clash, harm, harmony) and your favorable elements. Best hours combine almanac lucky hours with our Qi Men hour scores.

Ask Joss (Da Liu Ren)

  • Monthly general by mid-season solar term, heaven and earth plates, four lessons, the three transmissions by the nine classical methods, twelve generals and void branches.
  • The verdict (Clear / Cloudy / Wait it out) is our product rule set on top of the chart: the role of each transmission, the generals on the first and last, how the transmissions flow, and voidness. It is written down on this page, so you can check it.

Joss Timing (Qi Men Dun Jia)

  • Hour charts, rotating plate, chai-bu method. Every two-hour window in your range is scored for the event, and the direction comes from the palace that carries the event's key door or spirit.
  • Scoring weights are product choices, not classical constants.

What this is not

askjoss is for self-reflection and cultural enjoyment. It is not medical, legal, financial or psychological advice, and nothing we make guarantees luck, wealth or any outcome.