Two traditional systems
Personal directions use Eight Mansions (八宅). Annual and monthly charts use San Yuan Xuan Kong flying stars (三元玄空飛星). This slice does not calculate a full home chart, its facing direction or construction period.
Birth clocks and Li Chun
Your birthplace gives its IANA time zone and city-centre longitude. We convert the historical local clock time, including daylight saving, to the UTC+8 instant for solar-term year and month boundaries. A repeated clock time uses its first occurrence; a skipped time must be changed.
Male or female selects the traditional Kua formula and personal directions. A birth time adds the hour pillar; if you are not sure, we leave it out and use local noon for the year and month.
Kua and Eight Mansions
Let Y be the solar-term year. Male Kua = ((2 − Y) mod 9 + 9) mod 9; female Kua = (Y + 4) mod 9. Zero becomes nine, male five becomes two and female five becomes eight. Kan, Zhen, Xun and Li form the East group; Kun, Qian, Dui and Gen form the West group.
Sheng Qi, Tian Yi, Yan Nian and Fu Wei are traditionally favourable. Huo Hai, Liu Sha, Wu Gui and Jue Ming are directions for care. Their names do not predict an outcome.
Annual and monthly stars
The annual centre uses the raw male Kua formula, without mapping five. Flight order: centre, northwest, west, northeast, south, north, southwest, east, southeast. Each step adds one, wrapping nine to one.
Months start at the twelve jie solar terms. Tiger month starts at Li Chun; Ox month starts at Xiao Han and belongs to the previous solar year. Tiger-month centres: Rat/Horse/Rabbit/Rooster years = eight; Dragon/Dog/Ox/Goat = five; Tiger/Monkey/Snake/Pig = two. Each following month subtracts one, wrapping one to nine. The January chart starts at Xiao Han, not January 1.
Tai Sui and the 24 mountains
Tai Sui occupies the year branch mountain; Sui Po occupies the opposite branch mountain. Three Killings: Monkey/Rat/Dragon years south; Tiger/Horse/Dog north; Snake/Rooster/Ox east; Pig/Rabbit/Goat west. Mountains are 15° wide, with Zi centred on 0°. Degrees normalise to [0,360). A reading within 3° of a boundary gets a measurement note.
Zodiac relations include same, opposing, harm, break and punishment. Tiger/Snake/Monkey and Ox/Dog/Goat punishment sets are mutual; Rat/Rabbit are paired, with self-punishment for Dragon, Horse, Rooster and Pig.
Pillars and element counts
The day pillar uses the Gregorian Julian Day Number. The year pillar follows the solar year; the month pillar uses the jie month and Five Tigers rule. With a time, the Five Rats rule supplies the hour pillar.
For the birth day and hour, we use local solar time: add four minutes per degree of east longitude, then subtract the historical UTC offset in minutes. This removes daylight saving as well. This longitude-only rule is local mean solar time; it does not add the seasonal equation-of-time correction. The day changes at corrected midnight, not 23:00. Other places without longitude use local clock time.
The day master is the day stem element. Bars count visible stems and branches only: eight characters with time, six without. Hidden stems, seasonal strength, transformations and useful gods are omitted. These bars are not a strength score.
Symbolic colours and directions
Zodiac colours follow the branch element. Wood: east/southeast; Fire: south; Earth: northeast/southwest; Metal: west/northwest; Water: north. This simplified cultural mapping is separate from your personal directions.
Data and licences
Calendar, solar terms and almanac: lunar-javascript 1.7.7 (MIT). Hong Kong Traditional conversion: opencc-js 1.4.2 (MIT, with Apache 2.0 conversion data). The browser uses generated data without loading either library.
Almanac vocabulary preserves historical cultural records. It does not recommend medical, family, legal or financial decisions.
My Day: calculations and simplifications
The day ten god compares your birth day-master stem with the selected day’s stem, using the producing and controlling cycles and polarity. Daily readings use the selected calendar date, changing at midnight rather than 23:00. Birth-day pillars follow the birthplace solar-time rule below.
We compare the day branch with your birth sign, using the Li Chun year boundary: same branch, self-punishment, clash, punishment, harm, break, Six Harmony and Three Harmony. Tiger/Snake/Monkey and Ox/Dog/Goat punishment sets are mutual, with Rat/Rabbit paired and self-punishment for Dragon, Horse, Rooster and Pig. These are cultural categories, without predicted events.
Job elements follow a folk classification, used only as a perspective for work tips. Business owner/self-employed and Other have no assigned element. MBTI adjusts the style of tips only and is not part of traditional feng shui.
Today’s colours use the day stem element and the element it produces: a modern simplification, without a useful-god analysis. Directions combine your favourable Eight Mansions directions with the solar-month stars at Hong Kong noon, including on solar-term boundary days.
Submitting details on Today, Save, Open Today or importing a code stores your profile on this device. Codes contain birth data; Clear data removes the local profile.
Today’s rhythm uses a modern symbolic table for work, relationships, wellbeing and money, each from 1–5. Six or Three Harmony adds 1; clash, punishment, harm, break subtracts 1. Each group counts once and they can cancel. Values stay within 1–5. The seven-day chart averages the four areas; it is not an overall luck score.
The traditions behind lucky items
The daily lucky element follows today’s element when it matches or produces your core element. If today controls your core, use the element produced by today that produces your core; if your core controls today, use the element produced by your core that produces today. These are folk “bridging” rules. If your core produces today, use the element that produces your core as “support”.
He Tu pairs: Water 1 · 6, Fire 2 · 7, Wood 3 · 8, Metal 4 · 9, Earth 5 · 0. Colour follows the daily lucky element. Direction follows your four suitable directions, preferring the first without monthly star 2 or 5.
The bracelet uses a simple folk idea of filling what is least present: choose the lowest visible stem-and-branch element count. Ties favour the element producing your core, then Wood, Fire, Earth, Metal, Water. Pick the first crystal in that element matching your focus, or the first available. A focus adds a second crystal with that traditional association. This is not a full chart analysis or a claim about crystal effects.
How your details are used
Your birth date gives the pillars and day master, the element of the birth-day stem. These are traditional cultural references.
Male or female selects the traditional Kua formula and personal directions. A birth time adds the hour pillar; if you are not sure, we leave it out and use local noon for the year and month.
Your birthplace gives its IANA time zone and city-centre longitude. We convert the historical local clock time, including daylight saving, to the UTC+8 instant for solar-term year and month boundaries. A repeated clock time uses its first occurrence; a skipped time must be changed.
For the birth day and hour, we use local solar time: add four minutes per degree of east longitude, then subtract the historical UTC offset in minutes. This removes daylight saving as well. This longitude-only rule is local mean solar time; it does not add the seasonal equation-of-time correction. The day changes at corrected midnight, not 23:00. Other places without longitude use local clock time.
The current device supplies today’s date and time zone, including the week list and day page. Almanac tables follow that calendar date. Birthplace does not set today’s date. Old profiles without a birthplace keep the original UTC+8 calculation until you change details.
Submitting birth details saves them on this device. They are not sent to a server. The “more accurate” option uses more birth details; it does not promise predictions.
Daily luck with a zodiac sign only
Start at Steady. Six Harmony or Three Harmony with the day branch means Good; both means Great. A punishment link (including self-punishment), harm or break means Mind; a clash means Careful. Clashes take priority, then friction, then harmony. These levels describe traditional links, not the probability of events.
Lucky colours use the element of your year branch in place of the day master, following the existing daily element rule. Numbers come from the lucky element. Directions come from the traditional directions of your sign element, preferring those without monthly 2 Black or 5 Yellow. If all have these stars, the first direction is used with a keep-quiet reminder.
A full profile uses the existing personal daily advice and lucky-item rules. Its level is the mean of the four daily rhythm meters, rounded to 1–5. The week uses the same rule each day. Birth years start at Li Chun (Start of Spring). A year alone cannot resolve early-year birthdays; people born before Li Chun must choose the previous year.
We use the exact Li Chun instant, rather than Lunar New Year, to determine your zodiac year.