Parashara: the Brihat Parashara Hora Shastra · Chapter 4 of 9

#The six strengths

The BPHS turns Varahamihira's kinds of strength into a full arithmetic: shadbala, "six-fold strength", measured in virupas (60 virupas = 1 rupa) (BPHS 27).

#1. Positional strength (sthana bala, 27.1–6)

Five parts:

• Exaltation strength (uchcha): the planet's distance from its debilitation point, folded to at most 180°, divided by 3 — so 60 at exact exaltation, 0 at exact debilitation.
• Strength in seven divisions (saptavargaja): in each of D1, D2, D3, D7, D9, D12 and D30, a planet scores 45 in its moolatrikona, 30 in its own sign, 20 in a great friend's, 15 a friend's, 10 a neutral's, 4 an enemy's, 2 a great enemy's; the seven scores are added.
• Odd–even strength (ojayugma): 15 if the Moon or Venus is in an even sign, or another planet in an odd sign — counted in the sign and in the navamsa.
• Angular strength (kendradi): 60 in a kendra, 30 in a panaphara, 15 in an apoklima.
• Drekkana strength: 15 to male planets in the first drekkana of a sign, female planets in the second, neuter planets in the third.

#2. Directional strength (dig bala)

The distance from the point where the planet has no directional strength, folded to at most 180°, divided by 3. The zero points: the 4th house for the Sun and Mars (who are strongest in the 10th); the 7th for Jupiter and Mercury (strongest in the 1st); the 10th for the Moon and Venus (strongest in the 4th); the 1st for Saturn (strongest in the 7th) (27).

#3. Temporal strength (kala bala, 27.8–17)

• Day and night (nathonnata): the Moon, Mars and Saturn strongest at midnight; the Sun, Jupiter and Venus at noon; Mercury always 60.
• Lunar phase (paksha): the Moon's distance from the Sun, folded and divided by 3, for benefics; 60 minus that for malefics.
• Thirds of the day and night (tribhaga): the day's thirds to Mercury, the Sun and Saturn; the night's to the Moon, Venus and Mars; Jupiter always 60.
• Lords of the year, month, day and hour: 15, 30, 45 and 60.
• Declination (ayana): by the planet's declination north or south, with the Sun's doubled.
• Planetary war (yuddha): the difference in strength is added to the winner and taken from the loser.

#4. Motional strength (cheshta bala, 27.18–25)

For the Sun, equal to its declination strength; for the Moon, to its phase strength. For Mars to Saturn, from the planet's distance from its "conjunction" apex, folded and divided by 3 — greatest when retrograde. The eight kinds of motion carry their own values (27.21–23).

#5. Natural strength (naisargika bala, 27.14)

Fixed for every chart: 60 × n ÷ 7, with n = 7 for the Sun down to 1 for Saturn:

#6. Aspectual strength (drik bala, 27.19)

Plus a quarter of the benefic aspects received, minus a quarter of the malefic, plus the full aspect of Mercury and Jupiter — using the exact aspect values of chapter 26.

#The minimums (27.32–36)

A planet below its minimum is weak; above it, strong. The BPHS also gives minimums for the separate components (27.34–36), and remarks that a very strong Saturn gives long life with suffering.

#The strength of houses (bhava bala, 27.26–31)

Each house has a strength too: a base value from its sign's type, plus or minus a quarter of the aspects it receives, plus its lord's strength, plus 60 if Jupiter or Mercury occupies it and minus 60 for Saturn, Mars or the Sun, plus 15 if its sign suits the time of birth.

#Good and bad results (ishta and kashta, 28.2–6)

From each planet's exaltation and motional "rays" the BPHS derives two numbers, ishta (desirable) and kashta (painful), adding to 60: Ishta = [(exaltation ray − 1) × 10 + (motional ray − 1) × 10] ÷ 2, and Kashta = 60 − Ishta (28.2–6). They are used to weigh how much good and how much difficulty a planet's period will bring.

#Summary

• Shadbala has six parts — positional, directional, temporal, motional, natural and aspectual — each given as arithmetic in virupas (27).
• Minimum totals: Sun 6.5, Moon 6, Mars 5, Mercury 7, Jupiter 6.5, Venus 5.5, Saturn 5 rupas (27.32–33).
• Houses have their own strength (27.26–31); ishta and kashta weigh good and bad (28).

#Exercises

1. A planet is exactly at its exaltation point. What is its exaltation strength?
2. Where does Saturn have full directional strength?
3. What is Mercury's day-and-night strength, always?
4. Which planet has the highest natural strength, and how much?
5. What is the minimum total for Mercury in rupas?

Answers: 1. 60 virupas (180° ÷ 3). 2. In the 7th house. 3. 60. 4. The Sun, 60 virupas. 5. 7 rupas.