How Hongsil Builds a Saju Chart
What Hongsil asks for, how it turns a birth date into four pillars, where the written reading comes from, and what the tool does not do.
Hongsil is the saju reading we make at dotorium. It is in Korean, it is free, and it works without an account. This page explains what happens between typing in a birth date and getting a reading, so that anyone comparing it with another calculator can see which choices it makes.
What you enter
A reading starts with four things: a name or nickname to address you by, a date of birth, a time of birth if you know it, and gender. For a compatibility reading you enter the same details for the other person and choose the kind of relationship, from dating and marriage to friends and family.
The date can be given in the solar calendar or the lunar one. Lunar dates include a leap-month option, because a lunar year sometimes repeats a month and the two versions fall on different days. When you enter a lunar date, Hongsil converts it and shows the solar date it used, so you can check it against your own records.
If you do not know the time of birth, you can say so. The chart is then built from three pillars and six characters instead of four pillars and eight.
How the four pillars are set
The year and month pillars follow the solar terms, the twenty-four markers of the sun's position that the saju calendar is built on. The saju year turns at Ipchun, in early February, not on January 1 and not on Lunar New Year. Each saju month also begins at a solar term. Hongsil compares the moment of birth with the exact time of the term, so a birth on the day of Ipchun can fall on either side of the line depending on the hour.
The day and hour pillars use solar time, not clock time. Hongsil assumes a birth in Korea, where the clock runs roughly half an hour ahead of the sun, and subtracts the difference before working out the hour pillar. It also accounts for the periods when Korea observed daylight saving time and for the years when the country's standard time was set to a different meridian. When a birth time is entered and a correction applies, the adjusted solar time is printed above the chart so the correction is visible.
This is the most common reason two calculators disagree. A birth a few minutes after an hour boundary on the clock can sit in the previous two-hour block once the correction is made. Neither answer is a bug. They come from different conventions, and Hongsil states which one it uses.
What the result shows
The result page shows the pillars in a table, with the day pillar labelled, and gives the day pillar a nickname made of a color and an animal, such as a blue rat. Below that are five bars for Wood, Fire, Earth, Metal and Water.
The bars are a simple count. Each visible character in the chart belongs to one element, and a bar shows how many of the eight characters, or six without a birth time, belong to that element. An element with no characters is marked as lacking. The bars do not weight one position over another, so they are a first look at the balance of a chart and not a verdict on it.
Where the written reading comes from
The chart is calculated by code. The same birth details always produce the same pillars and the same bars.
The text of a reading is different. It is put together from passages prepared in advance for the features a chart can have, and where a chart is not covered, a passage is written by an AI model working from the calculated chart. Either way the wording is drafted with AI and is an interpretation in the saju tradition. It is not a prediction, and it is not medical, legal or financial advice. Hongsil avoids specialist terms where it can and explains a chart with the five elements in everyday Korean.
Readings cover love and compatibility, a general chart reading, money, work, wellbeing, and the year ahead. From October each year, the year-ahead reading looks at the following year.
What it keeps
Hongsil has no accounts. A reading, the details entered to make it, and any feedback left on it are deleted thirty days after the reading is made. The full policy is on Hongsil's own privacy page.
What it does not do
Hongsil does not ask where you were born, so it cannot correct for a birth outside Korea. If you were born abroad, convert your birth time yourself before relying on the hour pillar.
It does not show tables of hidden stems, the twelve life stages, or the full list of named patterns that specialist charts include. It is built for people meeting saju for the first time.
FAQ
Is Hongsil available in English?
Not yet. The tool and its readings are in Korean. The articles in this guide are the English-language part of the project.
Why is my hour pillar different from another site's?
Usually because of the solar-time correction described above, or because the two sites draw the line between days at a different point late at night. Check whether the other site adjusts for the difference between clock time and solar time.
Does a reading cost anything?
No. Readings are free and do not require signing up.
Related
- How to Read the Year, Month, Day and Hour Pillars
- Unknown Birth Time, Time Zones, and Why Saju Calculators Disagree
- Gunghap: How Koreans Read Compatibility in Saju
Part of the dotorium saju guide. Saju readings are for fun and reflection, not for making decisions.