Kairo
Korean Saju
Patterns before predictions
Saju Glossary: 50 Terms in Plain English
Every term a Saju chart or a Kairo reading uses, defined once in plain English with the Korean beside it.
Saju vocabulary is small. About fifty terms cover the whole chart, from the four pillars and eight characters through the Ten Gods, the ten-year cycles and the calendar rules underneath them. This glossary defines each one in a sentence or three, gives the Korean, hanja and romanization on first use, and says where the site has a fuller article. The definitions are the ones Kairo's engine and readings use.
The entries are grouped the way a chart is built: structure first, then the characters that fill it, then the elements those characters carry, then the relationships and cycles that interpretation works with, and finally the calendar rules that decide which characters you get. A last group covers words that appear on Kairo and nowhere else.
Structure of a chart
Saju (사주, 四柱, saju). Literally "four pillars". The Korean tradition of building a chart from the year, month, day and hour of birth and interpreting the relationships inside it. The site has a full introduction to what Saju is.
Four Pillars (사주, 四柱). The four stem-branch pairs that make up a chart: Year, Month, Day and Hour. Each pillar is one position in the sixty-pillar cycle.
Eight Characters (팔자, 八字, palja). The eight symbols in a chart: four Heavenly Stems on the top row, four Earthly Branches on the bottom row. In everyday Korean palja also means a person's lot in life. The site has an article on the eight characters.
Year Pillar (연주, 年柱, yeonju). The stem and branch of the birth year. In Saju the year changes at Ipchun, around February 4, and the branch is the animal most people know as their sign.
Month Pillar (월주, 月柱, wolju). The stem and branch of the birth month, where the month begins at a solar term rather than on the first of a calendar month. The Month Branch fixes the chart's season and carries more weight in interpretation than any other single branch.
Day Pillar (일주, 日柱, ilju). The stem and branch of the birth day. Days advance through the sixty-pillar cycle one per day, and the stem of this pillar is the Day Master.
Hour Pillar (시주, 時柱, siju). The stem and branch of the birth hour, using the twelve double-hours. If the birth time is unknown, this pillar is unknown; Kairo leaves it out and says so.
Day Master (일간, 日干, ilgan). The Heavenly Stem of the Day Pillar, and the reference point for the whole reading. Every other character is classified by its relationship to this one stem. There are ten possible Day Masters, and the site has an article on each.
Natal chart (원국, 原局, wonguk). The eight characters fixed at birth, as distinct from the cycles that move across them later. When a reading says "the natal chart" it means these eight and nothing added.
Stems and branches
Heavenly Stem (천간, 天干, cheongan). One of ten characters, each a fixed element and polarity: Gap 甲 and Eul 乙 are Wood, Byeong 丙 and Jeong 丁 are Fire, Mu 戊 and Gi 己 are Earth, Gyeong 庚 and Sin 辛 are Metal, Im 壬 and Gye 癸 are Water. The first of each pair is yang, the second yin. Stems sit on the top row of a chart.
Earthly Branch (지지, 地支, jiji). One of twelve characters that mark season, month and hour: Ja 子, Chuk 丑, In 寅, Myo 卯, Jin 辰, Sa 巳, O 午, Mi 未, Sin 申, Yu 酉, Sul 戌, Hae 亥. Each has an animal name, an element and a set of hidden stems. Branches sit on the bottom row. The site has a full article on stems and branches.
Sixty-pillar cycle (육십갑자, 六十甲子, yuksipgapja). The sequence produced by pairing the ten stems with the twelve branches in step, yang with yang and yin with yin. It begins at Gap-Ja 甲子 and returns there after sixty pairs. Years, months, days and hours are all counted on it, which is why 2026 (Byeong-O 丙午) has the same pillar as 1966.
Hidden stems (지장간, 支藏干, jijanggan). The one to three Heavenly Stems each branch contains. Ja holds Gye; In holds Mu, Byeong and Gap; Chuk holds Gye, Sin and Gi. The last stem listed is the branch's own element. Hidden stems are how an element absent from the visible eight characters turns up in a chart anyway.
Rooted (통근, 通根, tonggeun). A stem is rooted when a branch in the chart contains a hidden stem of the same element. A Gap Wood Day Master sitting on an In 寅 branch is rooted, because In holds Gap. Rooted stems are read as having support; unrooted stems are read as exposed.
Animal sign (띠, tti). The animal of the Year Branch: Rat, Ox, Tiger, Rabbit, Dragon, Snake, Horse, Goat, Monkey, Rooster, Dog, Pig. One character of eight. A person born in a Horse year has O 午 in the Year Branch and seven other characters that the animal says nothing about.
Elements and polarity
Five Elements (오행, 五行, ohaeng). Wood, Fire, Earth, Metal and Water. Every stem and branch belongs to one. The site has a full article on the Five Elements in Saju.
Wood (목, 木, mok). The element of Gap 甲, Eul 乙, In 寅 and Myo 卯. Its season is spring, the In and Myo months, roughly February 4 to April 4.
Fire (화, 火, hwa). The element of Byeong 丙, Jeong 丁, Sa 巳 and O 午. Its season is summer, roughly May 5 to July 7.
Earth (토, 土, to). The element of Mu 戊, Gi 己 and the four branches Jin 辰, Sul 戌, Chuk 丑 and Mi 未. Earth has no season of its own; its four branches sit at the end of each season as a transition month.
Metal (금, 金, geum). The element of Gyeong 庚, Sin 辛, Sin 申 and Yu 酉. Its season is autumn, roughly August 7 to October 8. Note that the stem Sin 辛 and the branch Sin 申 share a romanization and nothing else.
Water (수, 水, su). The element of Im 壬, Gye 癸, Hae 亥 and Ja 子. Its season is winter, roughly November 7 to January 5.
Yin and yang (음양, 陰陽, eumyang). The two polarities every character carries. Stems alternate yang, yin, yang, yin from Gap to Gye; branches alternate from Ja (yang) to Hae (yin). Polarity is what splits each of the five Ten-God families into two. The site has an article on yin and yang in Saju.
Generating cycle (상생, 相生, sangsaeng). Wood generates Fire, Fire generates Earth, Earth generates Metal, Metal generates Water, Water generates Wood. The element that generates the Day Master is its Resource; the element it generates is its Output.
Controlling cycle (상극, 相剋, sanggeuk). Wood controls Earth, Earth controls Water, Water controls Fire, Fire controls Metal, Metal controls Wood. The element the Day Master controls is its Wealth; the element that controls it is its Power.
The Ten Gods
Ten Gods (십성, 十星, sipseong; also 십신, 十神, sipsin). Ten labels that classify every other character by two questions: how its element relates to the Day Master, and whether its polarity matches. Five relationships times two polarities. The site has a full article on the Ten Gods.
Companion (비겁, 比劫, bigeop). The family of characters that share the Day Master's element. Same polarity is Bigyeon (비견, 比肩); opposite polarity is Geopjae (겁재, 劫財). Traditionally read around peers, self-direction and competition.
Resource (인성, 印星, inseong). The family of characters whose element generates the Day Master. Opposite polarity is Jeongin (정인, 正印); same polarity is Pyeonin (편인, 偏印). Traditionally read around learning, support and preparation.
Output (식상, 食傷, siksang). The family of characters whose element the Day Master generates. Same polarity is Siksin (식신, 食神); opposite polarity is Sanggwan (상관, 傷官). Traditionally read around expression, production and what a person puts out.
Wealth (재성, 財星, jaeseong). The family of characters whose element the Day Master controls. Opposite polarity is Jeongjae (정재, 正財); same polarity is Pyeonjae (편재, 偏財). Traditionally read around resources, management and exchange. Having a Wealth character in the chart says nothing about a bank balance.
Power (관성, 官星, gwanseong). The family of characters whose element controls the Day Master. Opposite polarity is Jeonggwan (정관, 正官); same polarity is Pyeongwan (편관, 偏官), also called Chilsal (칠살, 七殺). Traditionally read around authority, standards and pressure. The older translation "Seven Killings" for Chilsal is a naming convention from early English texts; Kairo's articles keep Chilsal beside it.
Time and cycles
Daewoon (대운, 大運). The ten-year cycles that move across the natal chart, each one a stem-branch pair taken in sequence from the Month Pillar. A person's first daewoon begins at a start age computed from the distance between the birth and the nearest solar term. The site has an article on why the 30s feel different that uses daewoon.
Sewoon (세운, 歲運). The annual pillar: the stem and branch of the current year, read against the natal chart and the current daewoon. In 2026 the sewoon is Byeong-O 丙午 for everyone; in 2027 it is Jeong-Mi 丁未.
Wolun (월운, 月運). The monthly pillar, changing at each solar term. The Mi 未 month of 2026 runs from July 7 to August 7.
Start age (대운수, 大運數, daewoonsu). The age at which the first daewoon begins, between 1 and 10 by the common rule. It is the one number in a chart that depends on the exact birth time and the exact solar-term timestamp together.
Forward and reverse (순행, 順行 / 역행, 逆行). The direction the daewoon sequence runs from the Month Pillar. It is set by the polarity of the Year Stem and the person's sex at birth: yang-year males and yin-year females run forward, the others reverse.
Calendar and calculation
Solar terms (절기, 節氣, jeolgi). Twenty-four points on the sun's annual path, fifteen degrees of ecliptic longitude apart. Twelve of them start the Saju months. The site has an article on solar terms versus lunar dates.
Ipchun (입춘, 立春). "Beginning of spring", the solar term at 315 degrees that starts the Saju year and the In 寅 month. In 2026 it fell on February 4 at 05:02 Korea Standard Time.
Seollal (설날). Lunar New Year, the first day of the first lunar month. In 2026 it was February 17. It is a holiday, and in folk usage it is when the animal sign changes; it is never a Saju boundary.
Manseryeok (만세력, 萬歲曆). The almanac, now usually software, that converts a civil date and time into stem-branch pillars. Two manseryeok tools disagree only when they use different conventions, for the time zone, for longitude, for the day boundary or for the solar-term timestamp. The site has a full article on manseryeok.
Double-hour (시진, 時辰, sijin). One of the twelve two-hour spans a day is divided into, each named for a branch. Ja 子 runs 23:00 to 01:00, Chuk 丑 01:00 to 03:00, and so on to Hae 亥 at 21:00 to 23:00.
Rat-hour and midnight convention (야자시, 夜子時 / 조자시, 早子時). Two rules for when the Saju day changes. Under the Rat-hour convention the new day starts at 23:00 with the Ja hour. Under the midnight convention it starts at 00:00, and the hour from 23:00 to midnight is a "late Rat hour" attached to the previous day. A birth at 11:20 pm gets a different Day Pillar under each rule. Kairo flags births near this boundary rather than choosing silently.
Longitude correction (진태양시 보정, 眞太陽時, jintaeyangsi). Adjusting clock time toward local solar time. Korea's clock runs on the 135°E meridian and Seoul sits near 127°E, so Seoul's mean solar noon comes about 32 minutes after 12:00 on the clock. Some schools shift every hour boundary by that amount; others use the clock as recorded.
Time zone and daylight saving. The legal clock in force at the birthplace on the birth date. Korea observed daylight saving in 1987 and 1988 and at no other time since 1961. The site has a full article on time zones and daylight saving.
Reading and interpretation
Seasonal command (득령, 得令, deukryeong). A Day Master has seasonal command when the Month Branch belongs to its own season or the season that generates it. Gap Wood born in the Myo 卯 month has it; Gap Wood born in the Yu 酉 month does not.
Strong and weak Day Master (신강, 身强 / 신약, 身弱). A summary judgement of how much support the Day Master has: from the season, from rooting in the branches, from Companion characters and from Resource characters. Strong is not better than weak. The label sets which Ten-God families a reading treats as balancing the chart.
Useful element (용신, 用神, yongsin). The element a practitioner judges the chart needs most. Different schools choose it by different rules, and two competent readers of the same chart can name different elements. Kairo treats the useful element as a school-dependent judgement and not as a property of the chart.
Combination (합, 合, hap). A pairing between characters that are read as binding to each other. Stems combine in five fixed pairs (Gap-Gi, Eul-Gyeong, Byeong-Sin, Jeong-Im, Mu-Gye). Branches combine in six pairs and in three-branch sets. A combination is a structural relationship, calmly described.
Clash (충, 沖, chung). A pairing between branches six positions apart: Ja-O, Chuk-Mi, In-Sin, Myo-Yu, Jin-Sul, Sa-Hae. Read as movement or tension between the two positions. A clash is a structural relationship, and it does not forecast an event.
Harm and punishment (해, 害 / 형, 刑). Two further branch relationships that exist in the tradition alongside clash and combination. They are lower-weight, schools disagree on how much they matter, and Kairo's articles rarely use them.
Void (공망, 空亡, gongmang). In each ten-day block of the sixty-pillar cycle, two branches go unpaired; those two are "void" for any pillar in that block. A classical technique that some schools use heavily and others ignore.
Gunghap (궁합, 宮合). Compatibility between two charts, traditionally checked before marriage. Kairo does not offer a compatibility reading.
Words you'll see on Kairo
Archetype. The block a chart falls into when the ten Day Masters are crossed with the four seasons of the Month Branch: 40 blocks in total. The free reading on the site sorts a chart into one of these 40. "Gap Wood in autumn" is an archetype; "The Pioneer Pattern" is the editorial name the site gives to Gap Wood in general.
Origin. Kairo's written reading of the natal chart, built for self-understanding.
Compass. Kairo's written reading built around a specific decision.
Pattern question. A question phrased so that you can check it against your own past behaviour, such as "in the last two projects you led, did you add scope after the deadline was set?" Kairo's articles use these in place of statements about who you are.
Boundary flag. A note the engine attaches when a birth falls within a short window of a solar term or of the midnight and Rat-hour boundary, meaning one pillar could differ under another convention.
What this glossary can and cannot tell you
A glossary fixes what the words mean. It does not say which words matter most in a given chart; a Chuk 丑 Month Branch changes the weight of every other entry above, and only a reading of the whole chart sets that weight. The useful element is judged differently by different schools, and the definition above gives the common form rather than a ruling. Everything under Reading and interpretation is a description of how the tradition reads, and none of it has been shown to predict outcomes.