Four Pillars & Derivations (四柱八字)

Complete BaZi (Eight Characters) analysis API. Computes the four pillars (year, month, day, hour) from a date, then derives all classical relationships: hidden stems, stem combinations and clashes, branch harmonies/clashes/punishments, ten relations, twelve life stages, element strength, void branches, virtue stars, and 30 almanac flags. Includes major and minor luck period computation.

Four Pillars (四柱)

Export	Description
`computeFourPillars(date)`	Compute year, month, day, and hour pillars

Hidden Stems (地支藏干)

Export	Description
`HIDDEN_STEMS`	`Record<Branch, HiddenStem[]>` — main, middle, residual stems
`getHiddenStems(branch)`	Hidden stems for a branch (main stem first)

Stem Relations (天干五合/相衝)

Export	Description
`STEM_COMBINATIONS`	Five stem combinations with transformed elements
`STEM_CLASHES`	Four stem clash pairs
`isStemCombination(a, b)`	Check if two stems form a 五合
`isStemClash(a, b)`	Check if two stems clash
`getCombinedElement(a, b)`	Transformed element of a combination, or null

Branch Relations (地支六合/六衝/三合/刑/害/破)

Export	Description
`HARMONY_PAIRS`	六合: 子丑, 寅亥, 卯戌, 辰酉, 巳申, 午未
`CLASH_PAIRS`	六衝: 子午, 丑未, 寅申, 卯酉, 辰戌, 巳亥
`THREE_HARMONIES`	三合: 申子辰水, 寅午戌火, 巳酉丑金, 亥卯未木
`SEASONAL_UNIONS`	三會: 寅卯辰木, 巳午未火, 申酉戌金, 亥子丑水
`HALF_HARMONIES`	半合: pairs from three-harmony groups
`PUNISHMENT_GROUPS`	刑: 寅巳申無恩, 丑戌未恃勢, 子卯無禮
`SELF_PUNISHMENT`	自刑: 辰午酉亥
`HARM_PAIRS`	六害: 子未, 丑午, 寅巳, 卯辰, 申亥, 酉戌
`DESTRUCTION_PAIRS`	六破: 子酉, 丑辰, 寅亥, 卯午, 巳申, 未戌
`isThreeHarmony(a, b, c)`	Check three-harmony group
`isPunishment(a, b)`	Check punishment relationship
`isSelfPunishment(branch)`	Check self-punishment
`isHarm(a, b)`	Check harm pair
`isDestruction(a, b)`	Check destruction pair

Hidden Harmony (暗合)

Export	Description
`HIDDEN_HARMONY_PAIRS`	Pre-computed pairs where main hidden stems form 五合
`isHiddenHarmony(a, b)`	Check if two branches have 暗合

Ten Relations (十神)

Export	Description
`TEN_RELATION_NAMES`	All 10 relation names
`getTenRelation(dayStem, otherStem)`	Derive the ten-relation
`getTenRelationForBranch(dayStem, branch)`	Ten-relation using main hidden stem

Twelve Life Stages (長生十二神)

Export	Description
`TWELVE_STAGES`	`['長生','沐浴','冠帶','臨官','帝旺','衰','病','死','墓','絕','胎','養']`
`getLifeStage(stem, branch)`	Life stage of a stem at a branch

Element Strength (旺相休囚死)

Export	Description
`STRENGTH`	`Record<Strength, string>` with descriptive labels
`getStrength(element, monthBranch)`	Seasonal strength: 旺, 相, 休, 囚, or 死

Earth Types (濕土/燥土)

Export	Description
`EARTH_BRANCHES`	`['辰','丑','戌','未']`
`isWetEarth(branch)`	辰丑 are wet earth
`isDryEarth(branch)`	戌未 are dry earth
`getStorageElement(branch)`	庫/墓: 辰→水, 戌→火, 丑→金, 未→木

Void Branches (旬空)

Export	Description
`computeVoidBranches(dayStem, dayBranch)`	`{ true: Branch, partial: Branch }` — 正空 (polarity match) and 偏空

Salary Star (祿神)

Export	Description
`SALARY_STAR`	`Record<Stem, Branch>` — stem → 臨官 branch
`getSalaryStar(stem)`	Get the 祿 branch for a stem

Virtue Stars (天德/月德)

Export	Description
`getMonthlyVirtue(monthBranch)`	月德: yang stem of the three-harmony element
`getHeavenlyVirtue(monthBranch)`	天德: traditional 12-entry lookup (stem or branch)
`getMonthlyVirtueCombo(monthBranch)`	月德合: 五合 partner of 月德
`getHeavenlyVirtueCombo(monthBranch)`	天德合: combination partner of 天德

Almanac Flags (神煞)

30 symbolic markers derived from stem-branch combinatorics:

Export	Description
`ALMANAC_FLAG_REGISTRY`	Full registry of all 30 flags with metadata
`getAlmanacFlags(date)`	All active flags for a date
`getAlmanacFlagsForPillars(pillars, season)`	All active flags from pre-computed pillars

Day stem derivations:

Export	Description
`getHeavenlyNoble(stem)`	天乙貴人: two noble branches
`getSupremeNoble(stem)`	太極貴人: supreme noble branches
`getLiteraryStar(stem)`	文昌貴人: literary star branch
`getProsperityStar(stem)`	祿神: prosperity branch
`getRamBlade(stem)`	羊刃: ram blade branch
`getGoldenCarriage(stem)`	金輿: golden carriage branch
`getStudyHall(stem)`	學堂: study hall (長生 position)

Branch derivations (三合 based):

Export	Description
`getTravelingHorse(branch)`	驛馬: from 三合 group
`getPeachBlossom(branch)`	桃花: from 三合 group
`getCanopy(branch)`	華蓋: from 三合 group
`getGeneralStar(branch)`	將星: from 三合 group
`getRobberyStar(branch)`	劫煞: from 三合 group
`getDeathSpirit(branch)`	亡神: from 三合 group

Branch derivations (other):

Export	Description
`getRedPhoenix(branch)`	紅鸞: red phoenix
`getHeavenlyJoy(branch)`	天喜: heavenly joy (紅鸞 + 6)
`getLonelyStar(branch)`	孤辰: lonely star
`getWidowStar(branch)`	寡宿: widow star
`getHeavenlyDoctor(branch)`	天醫: heavenly doctor (year branch + 1)

Day pillar predicates:

Export	Description
`isCommandingStar(stem, branch)`	魁罡: 庚辰/壬辰/庚戌/戊戌
`isTenEvils(stem, branch)`	十惡大敗: 10 specific day pillars
`isYinYangError(stem, branch)`	陰差陽錯: 12 specific day pillars
`isGoldSpirit(stem, branch)`	金神: 己巳/癸酉/乙丑
`isTenSpirits(stem, branch)`	十靈日: 10 specific day pillars
`isHeavenNet(branch)`	天羅: 戌/亥
`isEarthTrap(branch)`	地網: 辰/巳

Calendar predicates:

Export	Description
`isHeavensPardon(stem, branch, season)`	天赦日: seasonal pardon day
`isMonthBreak(dayBranch, monthBranch)`	月破: day clashes month
`isYearBreak(dayBranch, yearBranch)`	歲破: day clashes year
`isFourWaste(stem, branch, season)`	四廢: element dead in season

Multi-pillar patterns:

Export	Description
`getThreeWonders(pillars)`	三奇貴人: 乙丙丁 (天) / 甲戊庚 (地) / 壬癸辛 (人)

Luck Periods (大運/小運)

Export	Description
`getLuckDirection(yearStem, gender)`	Yang+male or yin+female → forward; opposite → backward
`computeMajorLuck(birthDate, gender, count?)`	大運: 10-year periods from month pillar (default 8 periods)
`computeMinorLuck(hourPillar, direction, fromAge, toAge)`	小運: year-by-year pillars from hour pillar

Types

typescript

interface Pillar { stem: Stem; branch: Branch; }
interface FourPillars { year: Pillar; month: Pillar; day: Pillar; hour: Pillar; }
type TenRelation = '比肩' | '劫財' | '食神' | '傷官' | '偏財' | '正財' | '七殺' | '正官' | '偏印' | '正印';
type LifeStage = '長生' | '沐浴' | '冠帶' | '臨官' | '帝旺' | '衰' | '病' | '死' | '墓' | '絕' | '胎' | '養';
type DayFitness = '建' | '除' | '滿' | '平' | '定' | '執' | '破' | '危' | '成' | '收' | '開' | '閉';
type AlmanacCategory = 'noble' | 'academic' | 'romance' | 'travel' | 'wealth' | 'protection' | 'health' | 'inauspicious';
interface AlmanacFlagInfo { name: string; english: string; auspicious: boolean; category: AlmanacCategory; }
interface AlmanacFlagResult extends AlmanacFlagInfo { positions: ('year' | 'month' | 'day' | 'hour')[]; }
type LuckDirection = 'forward' | 'backward';
interface MajorLuckPeriod { pillar: { stem: Stem; branch: Branch; stemBranch: StemBranch }; startAge: number; endAge: number; }
interface MajorLuckResult { direction: LuckDirection; startAge: number; periods: MajorLuckPeriod[]; }
interface MinorLuckYear { age: number; pillar: { stem: Stem; branch: Branch; stemBranch: StemBranch }; }
type PunishmentType = '無恩' | '恃勢' | '無禮';
type EarthType = '濕' | '燥';
type DayRelation = '生' | '剋' | '合' | '衝' | '比和';

Four Pillars & Derivations (四柱八字) ​

Four Pillars (四柱) ​

Hidden Stems (地支藏干) ​

Stem Relations (天干五合/相衝) ​

Branch Relations (地支六合/六衝/三合/刑/害/破) ​

Hidden Harmony (暗合) ​

Ten Relations (十神) ​

Twelve Life Stages (長生十二神) ​

Element Strength (旺相休囚死) ​

Earth Types (濕土/燥土) ​

Void Branches (旬空) ​

Salary Star (祿神) ​

Virtue Stars (天德/月德) ​

Almanac Flags (神煞) ​

Luck Periods (大運/小運) ​

Types ​