D3 Chart Calculator (Drekkana)

Thirds of a sign, signs of a trine

The rule takes one line. From 0° to 10° a body's drekkana is its own sign; from 10° to 20° it is the fifth sign counted from there; from 20° to 30° it is the ninth. Because the first, fifth and ninth signs from any sign share its element, every drekkana stays inside one triplicity — Aries runs Aries, Leo, Sagittarius; Taurus runs Taurus, Virgo, Capricorn.

There is no odd-and-even switch here, unlike the hora or the saptamsa, and no starting sign to look up. For the D3 degree, take how far the body has gone into its ten-degree slice and triple it: 13°20′ of a sign is 3°20′ into the second decanate, so 10° of the D3 sign.

Other drekkana schemes exist in the later literature, some of them counting from movable, fixed and dual signs instead of the trine. This page and the engine behind it use Parashara's; its signs were checked against that rule on six reference charts and matched every body.

Why siblings, and why the third house

When the classical text turns, in its seventh chapter, to what each division is for, it gives the drekkana to happiness through co-born brothers and sisters. The third house of any chart is the house of younger siblings, effort and nerve, so the D3 is in effect a magnified third house, and readers begin there.

A reader typically starts with the drekkana's rising sign and its ruler, moves to the D3 third house — its sign, its tenants, its ruler — and then checks Mars, natural significator of brothers and of daring, along with wherever the natal third lord has landed. All of it is weighed against the natal chart. The drekkana does not count siblings, and nothing on this page claims to.

The 1961 drekkana, step by step

The 1961 chart rises at 11°23′ of Scorpio, just past the first boundary, which is Scorpio's second decanate, and the fifth sign from Scorpio is Pisces, so the D3 lagna is Pisces at 4°10′ — the 1°23′ covered, times three.

Late Scorpio, where the Sun (27°25′), Mars (27°54′) and Mercury (25°34′) sit, is the last decanate, and the ninth sign from Scorpio is Cancer. Venus, 16°33′ in, is in the middle third and joins the lagna in Pisces. The Moon, 3°18′ into Aquarius, keeps Aquarius, the twelfth house. Jupiter, 13°07′ into Capricorn, moves to Taurus, the fifth from Capricorn, while Saturn, only 4°17′ in, keeps Capricorn. Rahu, late in Cancer, crosses to Pisces; Ketu opposite falls in Virgo.

Counting from Pisces, the third house is Taurus, and Jupiter alone occupies it. Its lord is Venus, which sits in the lagna, Pisces — the sign of Venus's exaltation. Cancer, the fifth, carries the Sun, Mars and Mercury together.

Where the lines fall

With boundaries at 10° and 20° there are only two places in a sign to watch. The example's lagna is about 1°23′ past the first, the kind of margin that turns on the birth time: the lagna moves through a ten-degree decanate in well under an hour on average, varying with latitude and the rising sign, and a slightly earlier birth would have left it in Scorpio's first decanate.

Among the planets, Saturn and the Moon sit comfortably inside their first decanates, the late-Scorpio trio is well past the 20° line, and Venus is roughly three and a half degrees short of it. Jupiter has cleared the first line by three degrees. So in this chart the planets' D3 signs are robust, and the houses hang on the lagna.

How to read the callout

Below the chart, a panel spells out the third house: its sign, anything in it, and the house and sign its ruler occupies. An empty third is common and means nothing alarming; the lord then carries the house. When the third is occupied, the occupants are read with the lord, not instead of it.

The drekkana also has a second, older use: the thirty-six decanate images describe a body's character in some classical texts. This page does not print those images or interpret them; it gives the chart, the third house and the lord, and leaves the reading to the person doing it.

The outer planets have no drekkana in the old scheme and are omitted, and the question of when is a matter for the dasha periods, not for this chart.

How is the drekkana chart calculated?

Split each sign into three parts of 10°. A body in the first part keeps its own sign, one in the second goes to the fifth sign from it, and one in the third goes to the ninth. Triple the distance into that slice for the D3 degree.

Which house of the D3 chart shows siblings?

The third, counted from the D3's own lagna. Readers note its sign, its occupants and its lord, then add Mars and the birth chart's third lord. They describe; they do not number anyone's brothers or sisters.

Is drekkana the same as drishkana or decanate?

Yes. Drekkana and drishkana are two spellings of the Sanskrit name, decanate is the Greek-derived word for the same ten-degree third, and D3 is the shorthand used in software. All four words point to one chart, built from thirds of signs.

Why does every drekkana stay in the same element?

Because the rule counts the first, fifth and ninth signs from the sign itself, and those three always share an element. A fire sign's three decanates are the three fire signs; an earth sign's are the three earth signs; and so on for air and water.

Does the D3 chart say whether I will have a brother or sister?

No — nothing here attempts that. The drekkana sets out the classical factors for siblings and courage as one part of a whole-chart reading. Family facts are facts; a chart is a description to be read against them, not a substitute for them.

Why did my D3 lagna change when I changed the birth time?

The lagna enters a new decanate every time the rising degree crosses 10° or 20° of its sign, which happens several times a day. Since all twelve D3 houses hang from that rising sign, a nudge to the time shifts them together; planets cross decanate lines much more rarely.