D4 Chart Calculator (Chaturthamsa)

Four quarters, four angles

The boundaries inside every sign fall at 7°30′, 15° and 22°30′. A body in the first quarter keeps its own sign. In the second it moves to the fourth sign from there, in the third to the seventh, and in the last to the tenth. Those are the angular houses counted from the sign, so the four quarters of Aries are Aries, Cancer, Libra and Capricorn — the four movable signs — and the quarters of Taurus are the four fixed signs.

As with the drekkana, the rule ignores whether a sign is odd or even. Multiply the arc already run inside the quarter by four and you have the D4 degree: 10° of a sign is 2°30′ into the second quarter and comes out at 10° again, while 18°45′ comes out at 15°.

Fortune in the text, property in practice

The text's seventh chapter, its catalogue of what each varga signifies, assigns the chaturthamsa to fortune. Practice reads it most often through the fourth house, the house of the home, the mother, land, vehicles of the household and the settled comfort that comes from them. The D4 is consulted when the birth chart raises a question about residence or immovable property and a finer look is wanted.

In practice one looks at the chaturthamsa ascendant and its ruler, then at the D4 fourth house — sign, tenants, ruler — then at where the natal fourth lord falls inside the D4, and finally at Venus and Mars, commonly taken as significators of comforts and of land. Each is one input among many. The chaturthamsa does not say whether or when anyone buys a house, and nothing here suggests otherwise.

The 1961 chaturthamsa

For the 1961 birth, the rising degree of 11°23′ Scorpio falls in Scorpio's second quarter. The fourth sign from Scorpio is Aquarius, so the D4 lagna is Aquarius, at 15°34′ — the 3°53′ covered inside the quarter, times four.

Aquarius 3°18′, the Moon's place, is the first quarter of its own sign, so the Moon stays in Aquarius, right on the D4 lagna. Scorpio's last quarter holds three bodies — Sun 27°25′, Mars 27°54′, Mercury 25°34′ — and sends them to the tenth from Scorpio, Leo, which is the seventh house from the Aquarius lagna. Venus, in Scorpio's third quarter at 16°33′, is sent to the seventh from Scorpio, Taurus. Two very different routes end in Aries: Jupiter from Capricorn's second quarter (13°07′) and Rahu from Cancer's fourth (27°41′). Saturn, 4°17′ into Capricorn, stays home in Capricorn, the twelfth; Ketu falls in Libra, the ninth.

From Aquarius the fourth house is Taurus, and Venus, the lord of Taurus, is the body sitting in it. A fourth lord in its own sign inside the fourth house is the cleanest callout this chart could give, and the panel under the chart records it without further comment.

Margins worth checking

With quarters only seven and a half degrees wide, the example has two placements on a fine edge. Venus is only a degree and a half into its quarter; Jupiter sits less than two degrees from the 15° line that would move it from Aries to Cancer. Both are slow enough at birth that the time of day does not change them.

The lagna is a different matter. It crosses a quarter in roughly half an hour on average — how fast depends on where on Earth the birth took place and which sign is rising — and the example's rising degree is about 3°36′ short of the next boundary. A birth time uncertain by an hour or so leaves the D4 lagna, and so every D4 house, open to doubt.

Using the result

The live result gives the chart, the fourth-house panel and a note. An empty fourth house is common and carries no warning of its own; the lord then speaks for the house, and a reader looks at its sign, its distance from the D4 lagna and its company.

Treat the chaturthamsa as a magnifying glass over the natal fourth house, never a replacement for it; the outer planets are not drawn, and the question of timing is left to the dashas.

How is the D4 chart calculated?

Cut each sign into quarters of 7°30′. Quarter one gives the sign itself, quarter two the fourth sign on, quarter three the seventh, quarter four the tenth. Four times the arc into the quarter is the D4 degree.

Is the chaturthamsa the same as the turyamsa?

Yes. Chaturthamsa and turyamsa both mean a fourth part, and D4 is the numbered shorthand. Each refers to the same quartered chart, whose quarters go to the sign and to its fourth, seventh and tenth signs.

Which house of the D4 chart is read for property?

The fourth, counted from the D4's own lagna, together with its lord and the birth chart's fourth lord as placed in the D4. Readers add Venus and Mars. Taken together they describe; they do not forecast a purchase or a sale.

What does Brihat Parasara Hora Sastra say the D4 is for?

Chapter 7, which gives each division its subject, assigns the chaturthamsa to fortune. Reading it for home, land and fixed assets is the practice that grew from its link with the fourth house.

Why is the D4 lagna so sensitive to the birth time?

Each quarter is only 7°30′ wide, so the rising degree crosses into a new one several times every couple of hours. The whole D4 house wheel turns with it, so a rough birth time can leave the chart one quarter off.