Saju and BaZi, where they differ

They compute the same eight characters

A birth moment gives a year, a month, a day and an hour. Each becomes a pillar of two characters, a heavenly stem above an earthly branch. Eight characters.

Both traditions do this identically. Same sexagenary cycle, same solar terms deciding when a month turns, same rule that the day advances at 23:00 rather than midnight. Feed one birth moment to both and the characters match.

So any comparison that claims one produces a different chart is describing a calculation error, not a difference between systems.

What genuinely differs

Vocabulary. BaZi calls the reference character the day master or 日主 rizhu; saju calls it the ilgan 일간. BaZi has the ten gods; saju has the sipseong, the same ten relationships in Korean. Characters are read with Korean pronunciations throughout.

Emphasis. A saju reading typically spends more of its length on the daeun 대운, the decade cycles, and is more willing to name the sinsal, the symbolic markers. A BaZi reading typically spends more on element balance, the strength of the day master and the structure of the chart. Both cover both; the proportions differ.

A handful of conventions. Traditions differ on some technical choices, such as how the direction of the luck cycle is set. These are documented positions rather than mistakes, and a reading should say which it follows.

Register. Saju in Korea is a normal thing to check before a decision. That practicality shows up in how readings are written.

How to choose

If your family or your interest is Korean, read in saju. The terms will be ones you have heard, and the framing will match how the subject is discussed.

If you came to this through Chinese metaphysics, feng shui or the five elements, read in BaZi. The vocabulary will connect to what you already know.

If neither applies, pick the one whose language you would rather live with, because that is the actual difference you will experience.

Reading both

Ordering both gives two accounts of one chart rather than two charts. Some people find the second reading does most of the work, because a pattern described twice in different vocabulary is easier to recognise than a pattern described once.

Common questions

Notes

Will a saju reading and a BaZi reading of my chart disagree?

On the chart, no. The eight characters are computed the same way, so both start from identical material. On emphasis, yes: a saju reading leans harder on the daeun cycles and the sinsal, a BaZi reading on element balance and structure. Two competent readings of one chart in two traditions read as two accounts of the same person.

Which one is more accurate?

Neither, because accuracy is a property of the calculation and the calculation is shared. What differs is which vocabulary is doing the explaining, and that is a question about you rather than about the systems.

Is one of them older?

The four-pillar method is Chinese in origin and travelled to Korea, where it developed its own practice, terminology and emphasis over centuries. Calling saju derivative would be wrong; it is a living tradition with its own texts and conventions, working on a shared method.