Zi Wei Dou Shu (紫微斗數), or Purple Star Astrology, is a profound and detailed system of Chinese astrology. It uses your precise birth date and time to plot a chart of 12 Palaces, each representing a different aspect of your life. This calculator will determine the foundational elements of your personal ZWDS chart: your Birth Year's Heavenly Stem and Earthly Branch, and the locations of your crucial Life Palace (命宮) and Body Palace (身宮).
Understanding Your ZWDS Chart
Unlike the more common 12 animal zodiacs, ZWDS provides a much deeper analysis of your destiny. The chart is a snapshot of cosmic energies at the moment of your birth.
The 12 Palaces (十二宮): These represent different domains of life, such as Self (Life Palace), Wealth, Career, Health, Relationships, and Parents. The stars that fall into these palaces influence their outcomes.
The Stars (星曜): There are over 100 stars in the ZWDS system, categorized into Major and Minor stars. The most important is the Zi Wei (紫微) or "Emperor" star, which gives the system its name. The position and brightness of these stars are key to interpretation.
Life Palace (命宮): This is the most important palace in your chart. It governs your fundamental personality, innate characteristics, potential, and the overall trajectory of your life.
Body Palace (身宮): This palace represents your acquired self, your physical body, and how you apply your efforts in the world. It often reflects your focus in the second half of your life.
Let's say someone was born on May 20, 1990, at 10:00 AM.
Birth Year: 1990
Birth Month: 5
Birth Day: 20
Birth Hour: 09:00 – 10:59 (Si 巳)
The calculator would determine the following:
Birth Year Pillar: Geng-Wu (庚午), corresponding to the Yang Metal Horse.
Life Palace (命宮) Location: Chou (丑) Branch.
Body Palace (身宮) Location: Hai (亥) Branch.
This information tells a ZWDS practitioner where to begin plotting the major stars on the chart. The Life Palace in Chou indicates the core personality traits, while the Body Palace in Hai reveals aspects of their later life and how they interact with the world.
Disclaimer: This calculator provides the foundational placements for a ZWDS chart. A complete and accurate reading requires the analysis of all stars, their brightness levels, and their complex interactions by an experienced ZWDS practitioner.
function calculateZWDS() {
var year = parseInt(document.getElementById('birthYear').value);
var month = parseInt(document.getElementById('birthMonth').value);
var day = parseInt(document.getElementById('birthDay').value);
var hourIndex = parseInt(document.getElementById('birthHour').value);
var resultDiv = document.getElementById('result');
if (isNaN(year) || isNaN(month) || isNaN(day) || isNaN(hourIndex)) {
resultDiv.innerHTML = 'Please fill in all fields with valid numbers.';
return;
}
if (year 2100) {
resultDiv.innerHTML = 'Please enter a year between 1900 and 2100.';
return;
}
if (month 12 || day 31) {
resultDiv.innerHTML = 'Please enter a valid month (1-12) and day (1-31).';
return;
}
var stems = ["Gui (癸 Water)", "Jia (甲 Wood)", "Yi (乙 Wood)", "Bing (丙 Fire)", "Ding (丁 Fire)", "Wu (戊 Earth)", "Ji (己 Earth)", "Geng (庚 Metal)", "Xin (辛 Metal)", "Ren (壬 Water)"];
var branches = ["Zi (子 Rat)", "Chou (丑 Ox)", "Yin (寅 Tiger)", "Mao (卯 Rabbit)", "Chen (辰 Dragon)", "Si (巳 Snake)", "Wu (午 Horse)", "Wei (未 Goat)", "Shen (申 Monkey)", "You (酉 Rooster)", "Xu (戌 Dog)", "Hai (亥 Pig)"];
var branchOnly = ["Zi (子)", "Chou (丑)", "Yin (寅)", "Mao (卯)", "Chen (辰)", "Si (巳)", "Wu (午)", "Wei (未)", "Shen (申)", "You (酉)", "Xu (戌)", "Hai (亥)"];
// Calculate Year Stem and Branch
var yearStemIndex = (year – 3) % 10;
if (yearStemIndex === 0) {
yearStemIndex = 10;
}
yearStemIndex = yearStemIndex – 1;
var yearBranchIndex = (year – 3) % 12;
if (yearBranchIndex === 0) {
yearBranchIndex = 12;
}
yearBranchIndex = yearBranchIndex – 1;
var yearStem = stems[yearStemIndex];
var yearBranch = branches[yearBranchIndex];
// Calculate Life Palace (命宮) and Body Palace (身宮)
// Life Palace starts from Yin (index 2), counts forward by month, then backward by hour.
var lifePalaceIndex = (2 + (month – 1) – hourIndex + 12) % 12;
// Body Palace starts from Yin (index 2), counts forward by month, then forward by hour.
var bodyPalaceIndex = (2 + (month – 1) + hourIndex) % 12;
var lifePalaceBranch = branchOnly[lifePalaceIndex];
var bodyPalaceBranch = branchOnly[bodyPalaceIndex];
var resultHTML = '
Your ZWDS Foundational Elements:
';
resultHTML += 'Birth Year Pillar: ' + yearStem + ' – ' + yearBranch + ";
resultHTML += 'Life Palace (命宮) Location: ' + lifePalaceBranch + ";
resultHTML += 'Body Palace (身宮) Location: ' + bodyPalaceBranch + ";
resultHTML += 'These positions determine the framework of your entire ZWDS chart. The Life Palace represents your core self, while the Body Palace reflects your acquired fortune and actions.';
resultDiv.innerHTML = resultHTML;
}