Saju vs BaZi vs Shichusuimei: One Chart, Three Vocabularies

Search for your birth chart in English and you will meet three names: saju from Korean, BaZi from Chinese and shichusuimei from Japanese. They are not three rival systems. All three describe the same four-pillar chart built from the same calendar. What changes from one language to the next is the vocabulary, a few naming habits and the techniques that are most popular. This guide sorts out what is shared, what is only a different word, and where two calculators can genuinely give you different charts.

For a first introduction to the chart itself, start with What Is Saju?.

Three names, one structure

The Korean phrase saju palja contains both ideas at once: four pillars, eight characters. Each pillar is a Heavenly Stem over an Earthly Branch, and four pillars give eight characters. You will also see the more scholarly Korean term myeongnihak (명리학, 命理學), the study of fate's principles, and the Chinese name Ziping, after Xu Ziping, a figure from the tenth century to whom the day-stem method is traditionally credited.

In English, all of these are often grouped as Four Pillars of Destiny.

What all three share

Whatever the name, the chart is built from the same parts:

• the ten Heavenly Stems, from 甲 to 癸, and the twelve Earthly Branches, from 子 to 亥;
• the sixty-pair cycle that runs through years, months, days and hours;
• the solar terms, which set the month boundaries and start the year at the beginning of spring, not on 1 January or at Lunar New Year;
• the five elements and yin–yang polarity carried by every character;
• the stem of the day pillar as the reference point for the self.

Given the same birth data and the same calculation rules, a Korean, a Chinese and a Japanese calculator produce the same eight characters.

Same idea, different words

Most confusion comes from vocabulary. The characters behind a term are often identical; only the reading changes.

Individual ten-god names vary too. The label English guides often call Seven Killings is usually 七杀 (qīshā) in Chinese, while Korean and Japanese sources more often use the gentler name 편관 (pyeongwan) and 偏官 (henkan), meaning "indirect officer". It is the same relationship to the Day Master under a different name. Ten Gods in Saju: How Each Stem Relates to Your Day Master shows how each label is worked out.

Where charts can really differ

If two sites give you different characters for the same birthday, the cause is almost never the tradition. It is a method choice, and it usually affects only births near a boundary:

1. When the day changes. Some schools start the new day at 23:00, the start of the Rat hour; others change it at midnight. A birth between 23:00 and midnight can land on different days, and so get a different Day Master.
2. Clock time or solar time. Some practitioners correct the clock for the birthplace's longitude or for true solar time. Korea's standard time, for example, is set to a meridian east of Seoul, so some Korean readers shift birth times by roughly half an hour. Others use the clock time as written.
3. Time-zone and daylight-saving history. Older birth records can sit in a different official time than today's.
4. Solar or lunar input. Entering a lunar birthday as a solar date moves the whole chart, not just one pillar.

The PillarAtlas calculator states its own choices: it uses the local clock time you enter, applies no time-zone or true-solar-time correction, changes the day at midnight and leaves the hour pillar open when the time is unknown. Saju Birth Time: What the Hour Pillar Needs explains what those choices mean for the hour pillar.

Where emphasis differs

Beyond the chart, readers in each language lean on different tools. Many Japanese calculators show a row of ten-god labels for the hidden stems as well as the visible ones. Many Chinese manuals give a lot of space to judging how strong the Day Master is and which element balances it. Korean practice sits inside a wider culture of saju cafés and apps, described in Korean Fortune Telling.

These are tendencies, not rules. Schools within each country disagree with one another as much as the countries do, so a teacher's lineage tells you more than their nationality.

Not the same: Zi Wei Dou Shu

One neighbouring system is often mixed up with the four pillars. Zi Wei Dou Shu (紫微斗數, 자미두수 jamidusu in Korean) also starts from a birth date and hour, but it places named stars into twelve palaces on a chart grid. It does not build four stem–branch pillars, so a Zi Wei chart and a saju chart are not interchangeable. If a site shows you twelve boxes full of star names, you are looking at Zi Wei, not saju.

How to use this when you compare sites

• Translate the terms first: 일간, 日主 and 日干 are the same position.
• Check the eight characters, not the headline label. If they are identical, the sites agree on the chart, however differently they describe it.
• If they differ, check the four method choices above before assuming either site is wrong.

Next step

Generate your four pillars and keep a note of the eight characters; they are the part every tradition shares. Free Saju Reading: What You Get Without Paying explains what the free chart on PillarAtlas includes.

Entertainment-only disclaimer

PillarAtlas charts and guides are for learning, self-reflection and entertainment. They are not medical, psychological, financial or legal advice, and no outcome is guaranteed.

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