About
What Ziwei is, how it calculates your chart, and who builds it.
Last updated: July 18, 2026
What is Ziwei
Ziwei is a web tool that draws and reads your Zi Wei Dou Shu chart from your birth date, time, and place. Anyone can use it right away with no sign-up, and unlike a plain horoscope that looks at your Sun sign alone, Ziwei unfolds the moment you were born across twelve palaces for a fuller picture of you.
What is a Zi Wei Dou Shu chart
Zi Wei Dou Shu is an Eastern form of astrology that converts the year, month, day, and hour of your birth into the sexagenary cycle to place the Purple Star and other stars across twelve palaces. The chart maps that arrangement: centered on the Life Palace, it reads the major stars and four transformations in palaces such as Siblings, Spouse, Wealth, and Career to describe your character and the areas of your life.
What you can do
Ziwei shows your birth chart across twelve palaces at a glance, reading the Life and Body Palaces, the 14 major stars with their auspicious and inauspicious companions, the four transformations (Lu, Quan, Ke, Ji), the Five Elements class, and the flow of the decade cycles. You can save or share your finished chart as an image, and every label and reading is available in Korean, English, Japanese, and Chinese.
How it calculates
Ziwei uses an open-source Zi Wei Dou Shu library as its calculation engine, with a notation layer on top that leads with the local language and shows the Chinese characters alongside. The time you enter is automatically corrected to true solar time using your birthplace’s longitude and the equation of time to fix the two-hour period, and every calculation runs entirely in your browser. Because birth time decides how the palaces are arranged, the more precisely you know the time, the closer the chart is to reality.
How your data is handled
The birth date, time, and place entered in the form are calculated in your browser and are not directly submitted to Ziwei’s server. If you choose to save them, they stay in this browser. If you choose link sharing, the birth details needed to reproduce the chart are included in the shared URL and delivered to anyone who receives it. See the Privacy Policy for storage, deletion, and sharing details.
Who builds it
Ziwei is built and run by sobok, a solo indie developer. It began with a simple goal: make Zi Wei Dou Shu easy to enjoy.
Please keep in mind
Ziwei’s readings are for self-reflection and fun, and are not a substitute for professional medical, legal, or financial advice. The full terms for using the service are in the Terms of Service, and if you have a question or suggestion, reach out through the Contact page.