Dangsaju (12 Stars) (당사주)

당사주 唐四柱 — The Twelve Stars Across the Four Ages of a Life

Overview

당사주 (Dangsaju) is a beloved Korean folk fortune system — the '당(唐, Tang) four pillars' — quite distinct from 사주(팔자), the Korean form of BaZi. Where saju weighs the interplay of the ten stems and their elements, Dangsaju does something simpler and more pictorial: it places the 십이성 (the Twelve Stars) onto your four birth pillars and reads your life as four ages — 초년 (early life), 중년 (middle life), 장년 (prime), and 말년 (late life). Each age receives one of twelve stars, from 天貴 (Nobility) to 天壽 (Longevity), and the pattern of auspicious and difficult stars across the four ages sketches the shape of a whole life.

Origin & history

Dangsaju is traditionally traced to the Tang-dynasty astrologer 이허중 (李虛中), and it entered Korea as a popular, accessible folk method — for centuries the version of fortune-telling most ordinary Koreans actually met, often illustrated with woodblock pictures of each star. Unlike the scholarly saju, it needs no element theory: it works on the lunar calendar with the twelve earthly branches alone, which made it easy to cast and to teach. Each of the twelve stars carries a small mythology of a spirit 'banished from heaven,' and its fortune bends according to which of the four life-stages it lands in.

The method rests on a fixed ring of twelve stars, one per earthly branch: 天貴 at 子, then 天厄, 天權, 天破, 天奸, 天文, 天福, 天驛, 天孤, 天刃, 天藝, and 天壽 at 亥. Seven are auspicious (天貴·天福·天權·天奸·天文·天藝·天壽) and five are difficult (天厄·天破·天驛·天孤·天刃). The reading walks the ring: your lunar-year branch (your 띠) gives the early-life star directly; then you step forward around the ring by the lunar month-number to reach the middle-life star, forward again by the lunar day-number for the prime-life star, and forward once more by the hour-branch for the late-life star. The count is inclusive and always forward — conventions the surviving Korean sources agree on.

How it works

Give a birth date (and, for the late-life star, a birth time). The engine converts the solar date to the lunar calendar (음력) — Dangsaju is a purely lunar method — and reads the 띠 (lunar-year) branch, which turns at 설날, NOT at 立春 as saju does. It places 天貴 at 子 on the fixed twelve-branch ring and takes the early-life (초년) star from the year branch. It then makes three inclusive forward steps: by the lunar month-number to the middle-life (중년) star, by the lunar day-number to the prime-life (장년) star, and by the hour-branch ordinal to the late-life (말년) star. Only the earthly branches are used; the heavenly stems are ignored entirely. Without a birth time, the late-life star is omitted. The four stars, each with its meaning and life-stage nuance, are returned together with the lunar date and your 띠 animal.

Good for

Use cases

The Four Ages

Send a birth date and get the star governing each life stage — early, middle, prime and late — the heart of a Dangsaju reading.

Early vs Late

The same star reads differently by age: a difficult star early can mean a hard start that eases; late, it concentrates its challenge in old age. The engine surfaces that nuance.

Auspicious & Difficult

See at a glance how the seven auspicious and five difficult stars fall across your four ages — where the life is supported and where it asks for care.

Lunar & 띠-Correct

Cast on the lunar calendar with the 띠 (설날) year boundary, the sourced-consistent method — not the 立春 boundary saju uses.

Key terms

십이성 (Twelve Stars)
The twelve stars of Dangsaju, one per earthly branch: 天貴·天厄·天權·天破·天奸·天文·天福·天驛·天孤·天刃·天藝·天壽 — seven auspicious, five difficult.
초년/중년/장년/말년
The four life-stages — early, middle, prime and late life — each read from one of the four birth pillars (year/month/day/hour).
天貴 (천귀)
The Star of Nobility, seated at 子 and the anchor of the fixed ring — brightness, honor, scholarship and rank.
띠 (lunar-year branch)
The Korean zodiac-animal branch of the lunar year, which turns at 설날 — the year basis Dangsaju uses (not the 立春 boundary of saju).
음력 (lunar calendar)
The lunar calendar Dangsaju is cast on; the month and day enter as their lunar numbers, and only the earthly branches are used.

API

The askTIAN Dangsaju endpoint casts the Korean Tang Four Pillars from a birth date. It converts the date to the lunar calendar, reads the 띠 (lunar-year) branch at the 설날 boundary, and places the 십이성 on the four pillars: the year branch gives the 초년 star, then three inclusive forward walks — by the lunar month-number, the lunar day-number, and the hour-branch — give the 중년, 장년 and 말년 stars. Only the earthly branches are used (the heavenly stems are ignored). It returns the four stars with their meanings, auspicious/difficult valence and life-stage nuance, the lunar date and your 띠 animal; without a birth time the late-life star is omitted. Deterministic and gold-locked to two published worked charts. A best-effort LLM reading is returned in parsable sections (set interpretation:false for structured data only). Honest rails: Dangsaju is a symbolic Korean folk tradition for reflection — sources differ on the day/hour stage labels and leap-month handling, all disclosed — and it is not a validated predictor, and not medical, legal or financial advice.

Endpoint: POST /trpc/korean.dangsaju — 3 TIAN Points. See the API documentation and Playground.