Many free saju tools quietly cut corners — January 1st year changes, lunar-month boundaries, ignoring where you were born. Here is exactly what we do instead.
We look up your birthplace's historical time zone, including daylight saving and past offsets (Korea used UTC+8:30 in the 1950s and daylight saving in 1987–88). If a clock time never existed or happened twice, we tell you. Birthplace search uses city data from GeoNames (CC BY 4.0).
If your family keeps your birthday on the lunar calendar (음력), switch the birthday field to Lunar and we convert it to the solar date first. We compute new moons and solar terms in Korea Standard Time, the way the Korean astronomy institute does — so a few dates differ by a day from the Chinese calendar (Korean New Year 1997 fell on Feb 8, the Chinese one on Feb 7). Leap months (윤달) are included for 1900–2100.
The saju year begins at the exact instant of the Start of Spring (立春, around Feb 4) and each month at one of twelve solar terms (節). We store astronomical times for 1900–2100 to the minute, in UTC, so the boundary is right wherever you were born.
Two-hour periods follow the sun at your birthplace's longitude (local mean solar time), not the clock. Seoul's clocks run about 32 minutes ahead of its sun, for example. The Rat hour (子時, 23:00–01:00) uses the common modern "split" method, and we flag births near any boundary.
Hidden stems use the Korean day-share convention, the twelve life stages follow the common Korean rule, and readings describe tendencies — never fixed fate.
Our engine reproduces a set of published reference charts (including solar-term edge cases and Korean daylight-saving births) and matched a widely used open-source calculator on 3,000 random birth moments.
Every chapter follows a written rulebook: name a challenge only together with a strength or something to try; one encouraging line per chapter; plain words, each saju term explained once (tap a dotted word for its meaning); no scare words. Chapters that break a rule, contradict your calculated elements or touch off-limits topics are thrown away automatically and replaced with our checked base text.
AI never calculates your chart. It helps write the reading in plain English from the calculated chart and a curated knowledge base, following strict rules: no predictions about health, death, pregnancy, divorce, money decisions or legal outcomes. Every reading is labeled as AI-assisted.
For entertainment and self-reflection, based on traditional Korean saju interpretation.
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