Brihat Jataka uses five divisions of a sign: the hora (halves), the drekkana (thirds), the navamsa (ninths), the dvadasamsa (twelfths) and the trimsamsa (five unequal parts). With the sign itself they make six charts, the set later books call the shadvarga. Each is counted the same way as in Parashara's longer list.
☕ The short list
Parashara lists sixteen vargas. Varahamihira, writing Brihat Jataka, keeps to a shorter set: the sign and five divisions of it (Brihat Jataka, ch. I, v. 9). When a planet holds the same sign in the rasi and in the navamsa, he calls it vargottama, and he counts that as a mark of strength.
The hora halves a sign; the drekkana cuts it into three parts of 10° (Brihat Jataka, ch. I, v. 11). In an odd sign the first hora belongs to the Sun and the second to the Moon; in an even sign the reverse. The three drekkanas go to the sign itself, then to its 5th and 9th signs.
The navamsa cuts a sign into nine parts of 3°20′ (Brihat Jataka, ch. I, v. 6). In a movable sign the count starts from the sign itself, in a fixed sign from its 9th, and in a dual sign from its 5th. Jataka Parijata gives the same start (Jataka Parijata (tr. Subramanya Sastri), ch. I, vv. 32–33, p. 20). The dvadasamsa cuts a sign into twelve parts of 2°30′, counted on from the sign itself.
The trimsamsa is the odd one out (Brihat Jataka, ch. I, v. 7). Its five parts are not equal, and the Sun and the Moon own none of them. In an odd sign the parts go to Mars, Saturn, Jupiter, Mercury and Venus; in an even sign the order turns round. This page gives the trimsamsa as a definition only. Each part and the sign it gives are in the card “Trimsamsa parts by sign” below.
The unequal division
- Odd sign: 0°–5° Mars (Mesha), 5°–10° Saturn (Kumbha), 10°–18° Jupiter (Dhanu), 18°–25° Mercury (Mithuna), 25°–30° Venus (Tula)
- Even sign: 0°–5° Venus (Vrishabha), 5°–12° Mercury (Kanya), 12°–20° Jupiter (Meena), 20°–25° Saturn (Makara), 25°–30° Mars (Vrischika)
- Mix-up: Brihat Jataka disagrees with Parashara on these five. The counting is the same; the books differ in how many vargas they use, not in how these are built.
- Mix-up: the trimsamsa is thirty equal parts of 1°. The name says thirty, but the five portions are 5°, 5°, 8°, 7° and 5°, which add up to 30°.
- Mix-up: the Sun and the Moon have a trimsamsa. They own none of its five parts; only the five other planets do.
Frequently asked questions
Why only five?
Brihat Jataka is a short book and keeps to the divisions it reads. The same six charts, the sign and these five, are the shadvarga that Parashara and later writers also use.
Does Nava use these five?
Yes. Nava draws the hora, drekkana, navamsa, dvadasamsa and trimsamsa with the same counting, beside the rasi chart and the other vargas.
Which planet rules a trimsamsa part?
In an odd sign the five parts go, in order, to Mars 5°, Saturn 5°, Jupiter 8°, Mercury 7°, Venus 5°; in an even sign the order is reversed. Parashara puts each part in a sign of its planet (Brihat Parashara Hora Shastra (Santhanam–Kapoor ed.), ch. 6, vv. 27–28, pp. 79–80): Mars's part of an odd sign falls in Mesha, Venus's part of an even sign in Vrishabha.
Deep dive: vargottama and the longer list
Where these five sit among the sixteen, and what this builds on.
🎯 Vargottama
A planet is vargottama when its navamsa sign is the same as its rasi sign. That happens in one navamsa of every sign: the first of a movable sign, the fifth of a fixed sign and the last of a dual sign. The page on vargottama and the varga grades goes further.
🧭 What this builds on
All sixteen divisions, and what Parashara reads each for, are on the sixteen vargas. A quick way to find a navamsa without a table is on working out a navamsa in your head.