Shadbala (六力)

The Six-Fold Strength — How Powerful Each Planet Truly Is

Overview

Shadbala (षड्बल, literally 'six strengths') is the answer Vedic astrology gives to the question a birth chart cannot: not where a planet sits, but how strong it actually is. A planet can be exalted yet powerless, or debilitated yet commanding — placement alone never tells you which. Parashara's Brihat Parashara Hora Shastra resolves this with a quantitative system that scores each of the seven classical planets on six independent axes of strength and sums them into a single number, measured in a unit called the Rupa (sixty Virupas to a Rupa). The six are Sthana Bala (positional strength — exaltation, dignity, the odd/even and angular placements), Dig Bala (directional strength — every planet rejoices in one of the four cardinal directions), Kala Bala (temporal strength — day or night, waxing or waning moon, the planetary hour), Cheshta Bala (motional strength — peaking when a planet is retrograde and closest to Earth), Naisargika Bala (the fixed natural brightness, the Sun strongest, Saturn weakest) and Drik Bala (aspectual strength — the net of benefic and malefic gazes falling on the planet). Each is compared against a required minimum: a planet that meets its threshold is strong enough to deliver what its placement promises; one that falls short struggles to. askTIAN computes the full Shadbala for any birth chart from its own precise sidereal astronomy, returns all six balas and their sub-parts for every planet, ranks them from strongest to weakest, and is candid that this is the most computationally divergent calculation in all of Jyotish — which is exactly why every constant and formula is locked by test and checked against a published reference chart.

Origin & history

Shadbala is set out in chapter 27 of the Brihat Parashara Hora Shastra, the foundational text of Vedic astrology attributed to the sage Parashara, and is elaborated in the works of later authorities such as Mantreswara's Phaladeepika and the writings of B. V. Raman in the modern era. Its premise is that the promise of a planet — read from its sign, house and aspects — can only be fulfilled in proportion to its strength, and that strength is not one thing but six, each measuring a different relationship between the planet and the cosmos. Sthana Bala measures the planet against the zodiac itself: how close to its exaltation degree, how dignified across the seven divisional charts, whether it occupies an angle from the ascendant. Dig Bala measures it against the horizon: Jupiter and Mercury are strongest rising in the east, the Sun and Mars overhead at the meridian, the Moon and Venus at the nadir, Saturn setting in the west. Kala Bala measures it against time: the diurnal/nocturnal division, the lunar fortnight (with the Moon's strength doubled), the thirds of day and night, the lords of the year, month, weekday and hour, and the planet's declination north or south of the equator. Cheshta Bala measures it against its own motion — the closer a planet to retrograde opposition, when it is nearest Earth and apparently moving backward, the stronger. Naisargika Bala is a fixed scale of natural brightness, and Drik Bala the algebraic sum of the aspects it receives. Together they give a planet's total in Rupas, the classical currency of planetary power.

For centuries Shadbala was the rigorous, arithmetic heart of predictive Jyotish — the tool that let an astrologer say not merely what a planet would do but how forcefully, and which of two planets would prevail when their significations clashed. It underpins the calculation of the Ishta and Kashta phala (a planet's capacity for benefic versus malefic results), feeds into Bhava Bala (the strength of the houses) and informs the weighing of yogas and dashas. Yet it carries a famous and honestly-acknowledged difficulty: Shadbala is the single most divergent computation in Vedic astrology software. The classical texts leave several sub-calculations underspecified — the exact method for the year and month lords, the treatment of Cheshta Bala for the inner planets, the precise aspectual weighting — and as a result no two programs fully agree. The respected open-source library PyJHora notes in its own documentation that its Shadbala values do not match those of the widely-used JHora software, and that the underlying algorithm of the latter is not publicly known. askTIAN meets this honestly: rather than claim a false bit-for-bit parity with any one tool, it locks every constant and formula it uses against the classical sources by unit test, names the conventions it adopts where the texts are silent, computes everything on its own pure-function Meeus ephemeris and Lahiri sidereal zodiac (the same one its Jyotish, Varga, Ashtakavarga and Panchanga engines share), and reproduces a published reference chart — the 'V. P. Jain' fixture distributed with PyJHora — within a stated, documented tolerance. Where its values diverge from another program, it tells you why.

How it works

askTIAN converts the birth date, time, timezone and place to a single instant and computes the true sidereal longitudes of the seven classical grahas — Sun, Moon, Mars, Mercury, Jupiter, Venus and Saturn — with its own Meeus-precision ephemeris on the Lahiri ayanamsa, along with the ascendant, midheaven and the four angles, the planets' declinations, and their direction of motion. From these it builds each of the six balas in Virupas. Sthana Bala sums five parts: Uccha (the planet's distance from its debilitation degree, scaled 0–60), Saptavargaja (its dignity summed across seven divisional charts D1/D2/D3/D7/D9/D12/D30, scored on the PVR/JHora halving series from moolatrikona down to great enemy, using the compound of natural and temporary planetary friendship), Ojhayugmarasyamsa (a bonus for odd or even placement by sign and navamsa), Kendradi (sixty in an angle, thirty in a succedent, fifteen in a cadent house) and Drekkana (a decanate bonus by planetary gender). Dig Bala scores each planet by its angular distance from the direction in which it is weakest. Kala Bala sums Nathonnata (diurnal/nocturnal), Paksha (the Moon–Sun elongation, with benefics gaining as the Moon waxes and the Moon's own value doubled), Tribhaga (the thirds of day and night, with Jupiter always strong), the Varsha, Masa, Vara and Hora lordships (computed from the weekday and the Chaldean planetary hour), and Ayana (from the planet's declination, the Sun's value doubled). Cheshta Bala uses a defensible pure-compute synodic-phase method — the planet's heliocentric phase relative to Earth, which peaks at retrograde opposition for both inner and outer planets — with the Sun's motional strength folded into its Ayana and the Moon's into its Paksha to avoid double counting. Naisargika Bala is the fixed brightness rank (sixty times the rank over seven), and Drik Bala is the net of the Parashari aspect curve, including the special full aspects of Mars, Jupiter and Saturn, with benefics adding and malefics subtracting. The six are summed to a total in Virupas, divided by sixty to Rupas, and compared to each planet's required minimum; the engine also returns the Ishta and Kashta phala as the geometric means of Uccha with Cheshta, ranks the planets, and gives a transparent 0–100 score that is simply the mean of each planet's strength ratio — never a fortune.

Good for

Use cases

Planetary Strength Dashboard

Send a birth chart and the API returns a ranked table of all seven planets by total Rupas, each with its six balas broken out and a strong/weak flag against the required minimum — a fully deterministic spine for a chart-strength feature, no LLM required.

Which Planet Wins

When two planets co-rule or contest a result, compare their total Shadbala in Rupas to judge which delivers its significations more forcefully — the classical use of the system in predictive work.

Ishta / Kashta Capacity

Read each planet's Ishta (benefic capacity) and Kashta (malefic capacity) phala from the engine's geometric means of exaltation and motional strength, to weigh how a planet is likely to express across a dasha period.

Layer Over the Vedic Suite

Sharing the same sidereal chart as Jyotish, Varga and Ashtakavarga, an app can show a planet's placement, its divisional dignities, its transit bindus and now its six-fold strength side by side — the complete classical picture of a graha on one ephemeris.

Key terms

Shadbala
Sanskrit for 'six strengths' (shad + bala) — Parashara's system for scoring each of the seven classical planets on six independent axes of strength and summing them to a single total, the quantitative measure of how powerfully a planet can deliver its significations.
Rupa / Virupa
The units of planetary strength. One Rupa equals sixty Virupas (shashtiamshas). Each bala is accumulated in Virupas; the total divided by sixty gives the Rupas compared against each planet's required minimum (Sun 5, Moon 6, Mars 5, Mercury 7, Jupiter 6.5, Venus 5.5, Saturn 5).
Sthana Bala
Positional strength — the sum of five parts: Uccha (exaltation distance), Saptavargaja (dignity across seven divisional charts), Ojhayugmarasyamsa (odd/even placement), Kendradi (angular/succedent/cadent house) and Drekkana (decanate by gender).
Dig Bala
Directional strength — every planet rejoices in one cardinal direction: Jupiter and Mercury in the east (ascendant), Sun and Mars at the meridian, Moon and Venus at the nadir, Saturn in the west. Strength scales with distance from the opposite, weakest, direction.
Kala Bala
Temporal strength — the sum of the diurnal/nocturnal split, the lunar fortnight (Paksha, the Moon's value doubled), the thirds of day and night, the year/month/weekday/hour lordships, and the planet's declination (Ayana, the Sun's value doubled).
Cheshta Bala
Motional strength — strongest when a planet is retrograde and nearest Earth (its synodic phase near opposition). askTIAN computes it from heliocentric phase; the Sun's motional strength is folded into Ayana and the Moon's into Paksha to avoid double-counting.
Naisargika Bala
Natural strength — a fixed scale of brightness, sixty times the planet's rank over seven: Sun 60, Moon 51.43, Venus 42.86, Jupiter 34.29, Mercury 25.71, Mars 17.14, Saturn 8.57. The one bala that never changes between charts.
Ishta & Kashta Phala
A planet's capacity for benefic (Ishta) versus malefic (Kashta) results, computed as the geometric means of its exaltation and motional strengths — Ishta = √(Uccha·Cheshta), Kashta = √((60−Uccha)·(60−Cheshta)).

API

The askTIAN Shadbala API computes the full six-fold planetary strength for any birth chart on its own self-verifying sidereal astronomy: for each of the seven classical grahas it returns all six balas in Virupas — Sthana (with its five sub-parts), Dig, Kala (with its sub-parts), Cheshta, Naisargika and Drik — the total in Rupas against the required minimum, a strong/weak flag and strength ratio, the Ishta and Kashta phala, and the full strength ranking with strongest and weakest named, plus a transparent 0–100 score and a fixed-section LLM reading. The method is locked to the Brihat Parashara Hora Shastra and PVR/JHora conventions on the Lahiri sidereal zodiac, the same chart the Jyotish, Varga, Ashtakavarga and Panchanga endpoints share. Shadbala is the most software-divergent computation in Jyotish, so askTIAN is candid about it: every constant and formula is locked by unit test, the published PyJHora 'V. P. Jain' chart is reproduced within a documented tolerance, and the conventions adopted where the classical texts are silent (the year/month lords, the Cheshta method, the aspectual weighting) are named in the payload. Bhava Bala (house strength) and Yuddha Bala (planetary war) are out of scope and surfaced honestly. Set interpretation:false for structured data only.

Endpoint: POST /trpc/shadbala.compute — 7 TIAN Points. See the API documentation and Playground.