Vedic Strength Systems — Specification (V-06)

Status: Draft specification · Task: V-06 · Updated: 2026-10-25 (revision 2: §3.4 reductions, §4.5 kala/chesta formulas) · Implements nothing: no runtime export is added by this document.

This document defines the strength systems the Vedic engine may later calculate, the inputs each factor needs, and which of those inputs Composer can already supply. It is the gate for V-07 ashtakavarga and V-19 audited strength system. A system or factor not fully defined here stays unadvertised.

1. Assumptions pending upstream tasks

V-06 formally follows V-01 (profiles) and reads Composer facts defined by C-01. Neither is frozen, so this specification uses the assumed identifiers below. When V-01/C-01 land, rename these identifiers to the frozen ones; no formula or table in this document depends on the spelling.

Rule-family ids such as strength.shadbala.naisargika are proposed names for V-17 bundles.

2. Systems in scope

Strength results always expose individual factors. An aggregate is returned only when every factor it sums is present (§4.4). Neither zero nor an estimate stands in for a missing factor.

3. Ashtakavarga

3.1 Definition

Eight contributors — Sun, Moon, Mars, Mercury, Jupiter, Venus, Saturn and lagna — each give a bindu (benefic point) to specific signs counted from the contributor’s own D1 sign. The seven Bhinna Ashtakavargas (BAV) belong to the seven planets; their sign-wise sum is the Sarvashtakavarga (SAV).

offset(contributor, sign) = ((signIndex(sign) − signIndex(contributor)) mod 12) + 1   // 1–12, inclusive count
BAV[target][sign] = count of contributors c where offset(c, sign) ∈ table[target][c]
SAV[sign]         = Σ over the seven targets of BAV[target][sign]

Sign indices come from Binder’s sign id (aries = 0 … pisces = 11). Ashtakavarga never reads a longitude degree, so sign-boundary behavior is entirely Binder’s half-open rule.

3.2 Inputs

Rahu and Ketu (the lunar nodes) are not contributors and have no BAV: querying their BAV returns null (unavailable), never zero.

3.3 Contribution table schema and invariants

The table is target → contributor → sorted unique offsets (1–12): 7 targets × 8 contributors. Load-time validation rejects a missing cell, duplicate offset, offset outside 1–12 or wrong total.

The unreduced SAV total is always 337 because each BAV total is independent of planetary placement. That invariant applies before any reduction; trikona and ekadhipatya shodhana change totals, so V-07 checks 337 only at the unreduced stage and records the reduction stage.

Reference row — Sun’s BAV (offsets from each contributor), used for fixture F-AV1 below:

Review gate: the remaining six BAV tables must be transcribed from one named edition of Brihat Parashara Hora Shastra (research §9), with edition and chapter recorded in the bundle manifest. The per-BAV totals above are the load-time check; V-07 does not start fixtures until a second reviewer has compared the transcription.

3.4 Reductions

Each result names its stage. Both reductions run on each of the seven BAVs separately, never on the SAV. The procedures below follow B. V. Raman, Ashtakavarga System of Prediction, as summarized in [R4], and agree with BPHS ch. 67–68 (Santhanam, vol. 2) once E4 is read as below. Both are implemented and parashari-lahiri@2 selects them.

Trikona shodhana. Trine groups: fire (aries, leo, sagittarius), earth (taurus, virgo, capricorn), air (gemini, libra, aquarius), water (cancer, scorpio, pisces). For each group, apply the first matching case:

Ekadhipatya shodhana. Runs on the trikona-reduced figures, for the five pairs ruled by one planet: Mars (aries, scorpio), Venus (taurus, libra), Mercury (gemini, virgo), Jupiter (sagittarius, pisces), Saturn (capricorn, aquarius). Cancer and Leo are never reduced. “Occupied” means a natal planet stands in the sign; convention AV-V1 selects whether Rahu and Ketu count (default: the seven planets only, as in [R4]). First matching case:

[R4] states E4 as “raise the unoccupied figure to match”, but in that case the unoccupied figure is already the larger one; BPHS ch. 68’s “made equal” therefore lowers it, as implemented.

Fixture F-AV4 (from [R4], Sun BAV of the Standard Horoscope): fire 5, 4, 5 → 1, 0, 1; earth 3, 4, 0 → unchanged; air 5, 3, 5 → 2, 0, 2; water 4, 5, 5 → 0, 1, 1.

3.5 Transit use

A transiting body’s sign reads the natal BAV/SAV value for that sign. Moving positions never recompute the tables (V-07, V-09).

4. Shadbala

Shadbala is six groups of factors in virupas (shashtiamsas); 60 virupas = 1 rupa. It is defined for the seven planets only; Rahu, Ketu and lagna have no Shadbala.

4.1 Factor catalog

Constant tables used above:

All numbers above are rulebook rows, not code constants (chart-core rule 5). Naisargika values are 60 × k / 7 for k = 7 … 1; the table stores the exact fractions and rounds only at output.

4.2 Named variants

A variant without a selected option makes its factor unavailable; the engine never picks one.

4.3 Input map and independent factors

A speed-dependent factor treats speedLongitude: null as unavailable, never as zero.

4.4 Completeness and result shape

A strength result for one planet lists every requested factor as either { factor, virupas, ruleIds } or { factor, unavailable: reason }. Group and total sums are present only when every member factor is present:

• Group complete: all factors of that group are available → group sum returned.
• Shadbala complete: all six groups complete → total virupas, total rupas and the planet’s required minimum are returned (rule table strength.shadbala.minimums, e.g. Sun 390, Moon 360, Mars 300, Mercury 420, Jupiter 390, Venus 330, Saturn 300 virupas — subject to the review gate).
• Otherwise complete: false with the missing factor list; no total, ratio or rank is published.

The first V-19 slice may advertise exactly the “Independent: Yes” factors as shadbala-partial; it must not advertise shadbala.

4.5 Kala and chesta formulas (revision 2)

Source [R1]: Brihat Parashara Hora Shastra ch. 27 with R. Santhanam’s notes (Ranjan Publications, vol. 1). Verse numbers are Santhanam’s. Each formula below is now defined, so each factor computes as soon as its input gate opens; until then it stays missing-capability.

Nathonnata (v. 8–9). Unnata = time between apparent midnight (SB-V6) and the birth instant, in ghatis (1 ghati = 24 minutes), at most 30. Nata = 30 − unnata.

Tribhaga (v. 12). Divide daytime [sunrise, sunset) and night [sunset, next sunrise) each into three equal parts (half-open, integer milliseconds as in muhurta). Jupiter always gets 60; one other planet gets 60 and the rest 0:

Abda, masa, vara, hora (v. 13). The lord of each period gets 15, 30, 45 and 60 virupas; others get 0. Weekday rulers are Sun, Moon, Mars, Mercury, Jupiter, Venus, Saturn for Sunday to Saturday. With A = days elapsed from the SB-V5 epoch to the birth day:

The epoch constant [R1] cites (Burgess’s Surya Siddhanta) is 714,404,108,573 days from creation to 1 January 1860. The base year is fixed by F-SB15: within 1840–1900 only 1860 reproduces all three of its lords (abda Jupiter, masa Venus, Friday), and the Kali-yuga epoch plus Burgess’s creation-to-Kali count independently lands in early 1860. Profile value surya-siddhanta-1860. Fixture F-SB15 pins the arithmetic: [R1]'s worked example (birth 1 June 1984, a Friday) gives A-quotient 181 → 181 × 3 + 1 = 544, 544 mod 7 = 5 → Thursday → Jupiter is the abda lord; the masa and vara lords are Venus.

Ayana (v. 15–17). With declination δ (kranti) in degrees and ε = 23°27′:

ayana = (ε + s × |δ|) × 60 / (2ε)        // ≈ (23.45 ± |δ|) × 1.2793, range 0–60
s = +1 for Sun, Mars, Jupiter, Venus with northern δ; Moon, Saturn with southern δ; Mercury always
s = −1 otherwise
Sun's ayana is doubled

[R1] uses the fixed 23°27′, not the obliquity of date (the current tilt of the ecliptic to the equator); the constant is a rulebook row.

Chesta (v. 24–25), Mars to Saturn only. Needs, per planet, its mean longitude (madhya) and its seeghrocca from the mean-longitude port, plus the Binder true longitude:

kendra = seeghrocca − (madhya + true) / 2, normalized to 0–360
if kendra > 180: kendra = 360 − kendra
chesta = kendra / 3                      // virupas, 0–60

Sun’s chesta equals its ayana bala and Moon’s equals its paksha bala (v. 18 notes); these need no extra input. The MeanLongitudePort reading carries seeghrocca (null for Sun and Moon).

Minimums (v. 32–36), retained for completeness checks. Totals: Sun 390, Moon 360, Mars 300, Mercury 420, Jupiter 390, Venus 330, Saturn 300 virupas (unchanged from §4.4).

4.6 Sources

5. Gates before full Shadbala

6. Formula fixtures

These fixtures check each formula against a hand calculation. They are not independent reference-chart fixtures; V-19 still needs published charts with known Shadbala values.

Boundary rules: arc uses the shared angular-separation primitive (no second implementation); decanate boundaries at 10° and 20° are half-open like sign boundaries.

7. Out of scope

• Interpretation of strong or weak planets, remedies or prose.
• Bhava bala, Vimshopaka, Ishta/Kashta phala and KP significator strength.
• Any astronomical quantity not returned by Binder; this document lists such gaps, it does not fill them.