Thai Maha Tak Sa (泰式八曜命盤)

The Eight-Fold Octad — Thai Weekday Astrology & the Art of the Auspicious Name

Overview

In Thailand a child's name is not chosen by sound alone — it is chosen by the stars of the day they were born. The framework that governs this is Maha Tak Sa (มหาทักษา), the 'great Tak Sa', an eight-fold octad in which the seven planets of the week — plus Rahu, the shadow-planet who rules Wednesday night — are seated around an eight-pointed wheel and read through eight houses of life: บริวาร the retinue, อายุ life and health, เดช power, ศรี fortune, มูละ assets, อุตสาหะ diligence, มนตรี patrons, and กาลกิณี misfortune. Your birth weekday decides which planet sits in your house of the self, and from there the whole octad falls into place — including the one planet that lands in the house of misfortune. That กาลกิณี planet owns a group of Thai letters, and to this day a Thai monk or astrologer naming a baby will avoid those letters and reach instead for the letters of the auspicious houses. askTIAN computes the entire octad from the birth weekday alone, names the planet of every house, identifies the letters to set aside and the letters to favour, and can score a Thai-script name against the wheel — candid throughout that this is cultural naming and character guidance, never a forecast of events.

Origin & history

Maha Tak Sa belongs to โหราศาสตร์ไทย, Thai astrology, a tradition that wove together the Indian jyotisha brought by way of the Khmer and Mon courts with Theravada Buddhist cosmology and local Tai belief. Its name comes from ทักษา, from the Sanskrit dakṣiṇā, 'the auspicious right-hand direction' — for the planets are counted clockwise (เวียนขวา) around the wheel, the direction of blessing. The system inherits the classical Indic scheme of the seven weekday planets and the lunar nodes, but gives it a distinctively Thai turn: it adds Rahu as a true eighth planet ruling the night of Wednesday, and it binds each planet to a class of Thai consonants drawn from the Pali varga (the ordered consonant-groups of the alphabet). This marriage of planet and letter is what made Tak Sa the backbone of Thai onomastics — the science of names — set down in naming manuals (ตำราทักษาปกรณ์) and still taught by temple astrologers and consulted at births across the country.

askTIAN is precise about what is canonical and what varies between practitioners. Firm and textual: the eight grahas and their order, the eight houses (ฐานทักษา) in their fixed sequence ending in กาลกิณี, and the assignment of each planet to its group of Thai letters — the eight letter-groups partition the Thai consonant set exactly, the Sun additionally taking the vowels. The placement rule is equally fixed: the birth weekday's ruling planet is seated at บริวาร, and the remaining planets fill the houses by walking the Thai octagon cycle — Sun, Moon, Mars, Mercury, Saturn, Jupiter, Rahu, Venus (the numeric path 1-2-3-4-7-5-8-6, in which Saturn precedes Jupiter) — so the planet of misfortune is always the one immediately preceding the birth-planet in the cycle. From this single rule the entire per-weekday กาลกิณี table follows, and askTIAN's table was triangulated across more than seven independent Thai naming sources with no genuine disagreement. Where the tradition does vary, askTIAN says so: some simpler tables omit the Wednesday day/night split (askTIAN keeps it, the one place birth time matters); the decorative animal-names of the letter-groups (นามสัตว์ — Garuda, Tiger, Lion…) come in competing orderings; and the obsolete consonants ฃ and ฅ are handled as belonging to the Moon group. Above all, the engine never declares a person or a day unlucky — only the single letter-group the naming tradition asks one to set aside.

How it works

Everything follows from the birth weekday by pure arithmetic — no ephemeris, no birth year. askTIAN converts the birth date to a Julian Day Number and takes it modulo seven to find the weekday, then the weekday's ruling planet: Sunday→Sun, Monday→Moon, Tuesday→Mars, Wednesday→Mercury, Thursday→Jupiter, Friday→Venus, Saturday→Saturn. Wednesday is the one day where the clock matters: a birth in the day portion (06:00–17:59) keeps Mercury, while a birth in the night portion (18:00–05:59) is ruled by Rahu, the eighth planet — so a time is consulted only for Wednesday births. The ruling planet is seated at บริวาร (the house of the self), and the engine then walks the fixed octagon cycle forward to seat all eight planets in the eight houses, so the planet that lands in กาลกิณี (the eighth, misfortune) is the one just before the birth-planet in the cycle. From the กาลกิณี planet the engine reads off the Thai letter-group to avoid; from the strongly auspicious houses — อายุ, เดช, ศรี and มนตรี — it gathers the letters to favour. If a Thai-script name is supplied, askTIAN scans it character by character, flags any กาลกิณี letters, notes the favourable letters present, and returns an auspiciousness score. It also reports the day's traditional colour and Buddha-image posture (ปางประจำวัน). The whole response is structured, with an optional best-effort LLM reading in five parsable sections and explicit honesty rails.

Good for

Use cases

Auspicious Name Check

Send a birth date and a Thai-script name and get back the กาลกิณี letters to avoid, the favourable letters present, any forbidden letters the name already contains, and an auspiciousness score — the deterministic core of a Thai baby-naming or name-rating product, no LLM required.

The Birth Octad

From a single date the engine returns the planet of every house — who holds your power (เดช), your fortune (ศรี), your patrons (มนตรี), your life (อายุ) and your misfortune (กาลกิณี) — a structured spine for a 'read my Thai astrology chart' feature.

Wednesday Day or Night

Supply a clock time for a Wednesday birth and the engine correctly assigns Mercury (day) or Rahu (night), changing the entire octad and the letters to avoid — the one case where Thai tradition splits a single weekday into two.

Cultural Day Lookup

Resolve any date to its Thai ruling planet, lucky colour and Buddha-image posture — useful for a Thai cultural-calendar, day-color (สีประจำวัน) or temple-app feature anchored on the same weekday-planetary logic.

Key terms

Maha Tak Sa (มหาทักษา)
The 'great Tak Sa' — the eight-fold weekday-planetary octad of Thai astrology, in which the eight planets are seated around a wheel and read through eight houses of life. From Sanskrit dakṣiṇā, the auspicious clockwise direction in which the planets are counted.
The eight grahas
The seven weekday planets — Sun (Sunday), Moon (Monday), Mars (Tuesday), Mercury (Wednesday day), Jupiter (Thursday), Venus (Friday), Saturn (Saturday) — plus Rahu, the shadow-planet who rules Wednesday night, giving Thailand a true eighth planet.
The eight houses (ฐานทักษา)
The fixed sequence of life-domains the planets are read through: บริวาร (retinue/self), อายุ (life/health), เดช (power), ศรี (fortune), มูละ (assets), อุตสาหะ (diligence), มนตรี (patrons) and กาลกิณี (misfortune).
Boriwan (บริวาร)
The first house, the retinue and the self, which always holds the birth weekday's own ruling planet — the seat from which the rest of the octad is counted.
Kalakini (กาลกิณี)
The eighth and final house, misfortune — held by the planet immediately preceding the birth-planet in the octagon cycle. Its group of Thai letters is the one the naming tradition asks a person to set aside; it never marks the person or the day as unlucky.
อักษรวรรค (letter-groups)
The assignment of Thai consonants to the eight planets, drawn from the ordered Pali consonant-classes (varga). The eight groups partition the Thai consonant set exactly, with the Sun additionally owning the vowels — the bridge between astrology and the art of naming.
Wednesday day / night
The single weekday Thai tradition splits in two: a birth from 06:00 to 17:59 is ruled by Mercury (พุธกลางวัน), a birth from 18:00 to 05:59 by Rahu (พุธกลางคืน) — the one place a birth time changes the octad.
ปางประจำวัน (Buddha posture)
Each weekday has a traditional Buddha-image posture and lucky colour (สีประจำวัน) — the reclining Buddha for Tuesday, the forest-retreat Buddha and the colour black for Wednesday night — reported alongside the octad.

API

The askTIAN Thai Maha Tak Sa API computes the eight-fold Thai weekday-planetary octad (มหาทักษา / ทักษาปกรณ์) from a birth date and surfaces the tradition's core use: auspicious Thai name-giving. The eight grahas — the seven weekday planets plus Rahu, who rules Wednesday night — are seated around the wheel and read through eight houses: บริวาร (self), อายุ (life), เดช (power), ศรี (fortune), มูละ (assets), อุตสาหะ (diligence), มนตรี (patrons) and กาลกิณี (misfortune). From one date the engine seats the birth-planet at บริวาร, walks the fixed octagon cycle (Sun, Moon, Mars, Mercury, Saturn, Jupiter, Rahu, Venus) to place all eight, and returns the planet of every house, the กาลกิณี letters to avoid, the favourable letters drawn from the auspicious houses, the day's colour and Buddha posture, and — if a Thai-script name is supplied — a name check with an auspiciousness score. Accuracy is the priority: the system is a pure function of the birth weekday (no ephemeris, no birth year), with birth time consulted only to split Wednesday into Mercury (06:00–17:59) and Rahu (18:00–05:59); the per-weekday กาลกิณี table (Sun→Venus, Moon→Sun, Mars→Moon, Mercury→Mars, Rahu→Jupiter, Jupiter→Saturn, Venus→Rahu, Saturn→Mercury) was triangulated across more than seven independent Thai sources and is locked by unit test together with the disjoint letter-group partition and worked examples. It is distinct from the Burmese Mahabote already in the catalogue. It is honest about scope: the octad, houses and letter-groups are canonical and textual, while the decorative animal-names and obsolete-letter handling are practitioner-variable; no person or day is ever called unlucky — only one letter-group is set aside. The whole reading is symbolic Thai cultural naming and character guidance, deterministic from the birth weekday, not prediction and not medical, legal, or financial advice. A best-effort LLM reading is returned in five parsable sections; set interpretation:false for structured data only.

Endpoint: POST /trpc/thaiTaksa.compute — 6 TIAN Points. See the API documentation and Playground.