The Two Ashtakavarga Reductions: Trikona and Ekadhipatya Shodhana

☕ Two passes over one chart

Both reductions work on one chart at a time: a planet's own ashtakavarga chart, or the lagna's. The first groups the twelve signs into four trines, in “The four trines” further down (Brihat Parashara Hora Shastra (Santhanam–Kapoor ed.), ch. 67, vv. 1–2, p. 867). In each trine the smallest count is taken from all three signs: a trine already holding a zero stays as it is, and three equal counts all become zero (ch. 67, vv. 3–5, p. 868).

The second looks at the five planets that rule two signs each, in “The five lords of two signs” further down; the Sun and the Moon rule one sign each, so theirs are left alone (ch. 68, vv. 1–5, pp. 875–876). It works only when both signs of a pair still hold a number. If both signs hold planets, nothing changes. If both are empty, equal numbers both become zero and unequal ones both take the smaller. If one holds a planet, the empty sign goes to zero when the other holds as much or more, and otherwise loses the other's number. Only the seven planets make a sign occupied; Rahu and Ketu do not.

Here is Jupiter's chart for a sample horoscope with Jupiter in Mesha (Aries), Mars in Mithuna (Gemini), Sun and Venus in Simha (Leo), Mercury in Kanya (Virgo), Moon in Makara (Capricorn) and Saturn in Kumbha (Aquarius), worked out by Nava in the card “A sample chart, step by step” below. In the trine Mesha (Aries), Simha (Leo) and Dhanu (Sagittarius) the counts are 6, 2, 4; the least is 2, and taking it from all three leaves 4, 0, 2. In the pair Mesha (Aries) and Vrischika (Scorpio), Mesha (Aries) holds a planet and Vrischika (Scorpio) does not; after the first step they hold 4 and 1, and after the second 4 and 0.

Why do it? The reduced counts are the input to the pinda: each sign's reduced count times a fixed factor for the sign, added up, plus the counts of the signs that hold planets times a factor for each planet (ch. 69, vv. 1–4, p. 878). The books then use the pinda in timing rules that this page does not cover. Nava's engine works out both reductions for every chart, but nothing on screen reads them yet: the sign totals and the transit grades are read on the raw counts, as both books read them. Nava does not show the reduced counts.

Jataka Parijata gives the same first rule, then a second that lowers the other two signs to the smallest instead; its translator calls that the practice of South India and works his example by it (Jataka Parijata (tr. Subramanya Sastri), ch. X, vv. 37–38, pp. 685–686). Its second reduction differs from Parashara's on one case (ch. X, vv. 39–42, pp. 686–688).

What Nava follows: Parashara's verses for both steps. In the first, the least is taken from all three signs, as Jataka Parijata's own sl.37 also says, not the next sloka's South Indian rule. In the second, the verses rather than the book's illustration, which breaks them on two pairs; where both signs are empty and unequal, a case the translation leaves unclear, both take the smaller number, as the verse reads; and where the planet's sign holds the smaller number, it is taken from the empty sign, where Jataka Parijata sets the empty sign equal to it.