To build an accurate Saju (Four Pillars) chart you need four pieces of information: your birth date, your birth time (as exact as possible), your birthplace, and whether the date is solar or lunar. The date and time set your four pillars; the place and calendar type make sure they are calculated correctly.
The one that changes the result most is birth time. It sets your Hour Pillar and your Day Master’s exact position, which drive personality and timing. If you do not know your exact time, a reading is still useful for the year, month, and broad patterns — you just lose the hour-level detail.
Before your first Saju reading, here is precisely what to gather and why each detail matters, so your chart is built on the right foundation.
| Detail | What it sets | How precise? |
|---|---|---|
| Birth date | Year, Month, and Day pillars | Exact calendar date |
| Birth time | Hour Pillar; refines the Day Master | To the hour if possible |
| Birthplace | True solar time correction & time zone | City is enough |
| Solar or lunar | Which calendar the date is read in | Must be correct |
You can still get a meaningful reading. Without an exact time you lose the Hour Pillar and some fine timing, but the Year, Month, and Day pillars — which carry your Day Master, core personality, career and relationship tendencies, and annual luck — are still fully readable. A good tool will tell you clearly which parts depend on the missing hour.
Accuracy, in short, is mostly about getting these four inputs right. A precise calendar engine does the rest.
Cheonmyeongdang applies true solar time correction and handles solar or lunar dates automatically, so your four pillars are calculated correctly from the start. Enter your details and get your free chart in seconds.
Start My Free Saju ReadingFour things: your birth date, your birth time (as exact as possible), your birthplace, and whether the date is solar or lunar. The date and time build your four pillars, while the place and calendar type ensure they are calculated correctly with true solar time.
It helps a lot but is not strictly required. Birth time sets your Hour Pillar and refines your Day Master, so it adds hour-level detail and precise timing. Without it, your Year, Month, and Day pillars, which carry personality, career, relationships, and annual luck, are still fully readable.
Saju uses true solar time, not clock time. Your birthplace lets the calculation apply a true solar time correction and the correct time zone, which matters most for births near midnight or near an hour boundary, so the chart lands on the correct day and hour.
Yes, it is essential. Many people born in East Asia have a lunar date on record. If a lunar date is read as if it were solar, the pillars come out wrong entirely, so the reading must know which calendar your date is in.