Data Saju › About
About Data Saju
Data Saju is a free Korean saju (Four Pillars / BaZi) site built around one idea: every calculation should be checkable, and every reading should show the reasons behind it.
Who makes it
The Scribe
A software and data engineer with 13 years' experience — the person who built Data Saju
I have worked in software quality and data engineering, and built the engine the same way: from the exact moment of each solar term to 10-year, annual and monthly luck, every step can be verified. On the site, the Scribe is the voice that explains how each result was calculated.
Master Han AI
The site's AI saju reader (the Korean name of the site, 한도사, means "Master Han")
An AI character modelled on a teacher who has studied saju for many years. The engine does the calculating; Master Han reads the results and explains them. The rule tables and reading criteria are being refined with review from a long-time student of saju (who prefers not to be named). Master Han's individual answers are written by AI and can be wrong.
Data Saju is free. Each AI answer costs a little in server fees, so if it helped you, you can ☕ buy the Scribe a coffee. Everything works the same either way — tips are simply support.
How it calculates
Data Saju computes the position of the sun astronomically to find the exact time of each solar term, and sets the year and month pillars from them — so a month changes at its solar term, not on the 1st. The day pillar follows the sixty-day cycle, and the hour pillar uses local solar time at your birthplace. For births outside Korea, the engine applies your birthplace's historical time zone and daylight saving time before converting to local solar time. Supported dates run from 1900 to 2100.
Some choices differ between schools — for example, which day the 11 pm–1 am hour (子時) belongs to — and the Korean version lets you change these in advanced settings.
Please note
Everything on Data Saju is based on traditional saju and is offered for reflection and fun. For health, money, legal or career decisions, follow your own judgement and the advice of professionals. AI answers can be inaccurate or general.
Image credits
The header illustrations use Microsoft's Fluent Emoji (3D), released under the MIT License. The full license text is on the Korean About page.
How we write articles, check calculations and correct mistakes is set out in our editorial policy.
Contact
For bug reports or questions: 5253183asd@naver.com