Chaturthamsa D4 Chart

What this section adds

The calculator above returns a D4 sign and a D4 house for your Ascendant and nine grahas, and the notes beside it explain the code in two paragraphs. This section goes further: where the rule is written and how little the old text actually says about it, a full lookup table so you can check any result by hand, what each field of the answer means, where this app reuses the same ten D4 signs, what a modern case-study book does with the chart, and how many minutes of birth-time error it takes to change the picture. Every number comes from the engine, run on the same sample birth the page uses.

Where the Chaturthamsa rule is written

Brihat Parashara Hora Shastra names sixteen divisions of a sign in Ch. 6 Sl. 2-4: Rasi, Hora, Dreshkan, Chaturthamsa, Saptamsa and so on up to Shashtiamsa. The quarter division is fourth on that list, straight after Hora (D2) and Drekkana (D3). Its entire definition is one sloka, Ch. 6 Sl. 9. In the translation in our corpus it reads, in substance: the lords of the four kendras from a sign are the rulers of that sign's four Chaturthamsas, each Chaturthamsa is one fourth of a sign, and the deities of the four quarters are, in order, Sanak, Sanand, Kumar and Sanatan.

Three things in that sloka are worth separating. First, the size: a sign is 30 degrees, so a quarter is 7 degrees 30 minutes. Second, the mapping: the kendras from a sign are its 1st, 4th, 7th and 10th, a definition BPHS itself gives in Ch. 7 Sl. 33-36, where the kendras are named as Lagn, Bandhu Bhava, Yuvati Bhava and Karm Bhava. So the first quarter of a sign belongs to the sign itself, the second to the fourth sign from it, the third to the seventh and the last to the tenth. Third, the deities: four names attached to the four quarters in order.

The sloka also carries the phrase 'commencing from Mesh'. The engine's own comment on this line reads it as meaning that the count is taken from the sign in question, which for Mesh (Aries) gives Aries, Cancer, Libra and Capricorn, and the code applies the same pattern to every sign. That reading is the one the kendra wording requires: a quarter can only be ruled by 'the lord of a kendra from a Rasi' if the count starts at that Rasi.

BPHS gives zodiac totals for the two coarser cuts - 24 Horas in Sl. 5-6 and 36 Dreshkanas in Sl. 7-8 - but not for the quarters. By the same arithmetic there are 48 of them, twelve signs times four.

The complete quarter table

Because the rule has no odd-sign or even-sign branch, the whole of D4 fits in one table of twelve rows. Find the Rasi sign of the point on the left, find which quarter its degree falls in, and read the D4 sign. The lord of that quarter, in BPHS's sense, is simply the lord of the sign named in the cell.

Three patterns fall out of the table, and each is a quick test of any D4 chart you are shown.

• Every row stays inside one group of four signs. Aries, Cancer, Libra and Capricorn only ever map to each other; so do Taurus, Leo, Scorpio and Aquarius; so do Gemini, Virgo, Sagittarius and Pisces. These are the movable, fixed and dual signs of the classical threefold classification. A point in a fixed sign can never have a movable or dual D4 sign. If a D4 chart shows a Leo Ascendant turning into Gemini, the arithmetic is wrong.
• The first column repeats the row label. Only a first-quarter point keeps its sign, which is the vargottama rule the page's own FAQ explains.
• Each D4 sign is reached from exactly four places: its own first quarter, and one later quarter of each of the other three signs in its group. D4 Aries, for instance, comes from the first quarter of Aries, the second of Capricorn, the third of Libra and the fourth of Cancer.

Compare this with the neighbouring cuts. Drekkana steps across the trines, the 1st, 5th and 9th (BPHS Ch. 6 Sl. 7-8), so it keeps a point inside its element group. Chaturthamsa steps across the kendras and keeps it inside its modality group. Saptamsa (D7) and Navamsa (D9) walk through consecutive signs and keep neither. The code expresses the difference as a single number: a step of 4 signs per part for D3, 3 for D4, and 1 for the consecutive vargas.

How the engine computes it, line by line

The page's method notes describe the division and the step. Here is the full sequence as it runs in computeVarga, the shared routine in services/kundaliEngine.js that computeChaturthamsa calls with 4 divisions, a start function that returns the sign itself, and a step of 3.

1. 1.The handler builds a sidereal chart from your date, time and place with computeChart. The request is only accepted when a time and a resolved place are both present, because the handler is registered with needs: 'ascendant'.
2. 2.Ten points are collected: the Ascendant, then Sun, Moon, Mars, Mercury, Jupiter, Venus, Saturn, Rahu and Ketu. Each carries a Rasi sign and a degree within that sign.
3. 3.The arc of one part is 30 divided by 4, which is 7.5 degrees.
4. 4.The quarter index is the degree within the sign divided by 7.5, rounded down, giving 0, 1, 2 or 3. It is capped at 3 so that a value which reaches 30 through floating-point rounding cannot spill into a fifth quarter.
5. 5.The D4 sign index is the Rasi sign index plus the quarter index times 3, taken modulo 12. Three signs forward is the fourth sign counted inclusively, which is how a step of 3 lands on the kendras.
6. 6.The point is flagged vargottama when its D4 sign equals its Rasi sign.
7. 7.The D4 sign of the Ascendant becomes house 1, the next sign house 2, and so on for twelve whole-sign houses. Each graha's house is its D4 sign counted from that first sign.

Nothing else happens. The routine does not read aspects, dignity, combustion or retrogression, and it does not attach the four deities of Sl. 9 to the result. A boundary degree belongs to the later quarter: exactly 7.5 divided by 7.5 is 1, so 7°30'00" is already the second quarter, and 15° exactly is the third.

Checking a result with Saravali's rule

Saravali Ch. 3 Sl. 17-18 gives a method for any varga: a sign has 1800 kalas (minutes of arc); convert the longitude to minutes, multiply by the varga figure, and divide by 1800. Applied to the degree within the sign, the whole-number part of the answer is the number of completed parts. Take the sample's Jupiter at 13.55 degrees of Libra. That is 813 minutes; times 4 is 3252; divided by 1800 is 1.81. One quarter is complete, so Jupiter is in the second quarter, and the second quarter of Libra in the table is Capricorn. The engine returns Capricorn. The two routes are the same division written two ways, which is the point of doing it: you do not need to trust the code to confirm a row.

The sample chart, worked in full

The example above the fold shows the D4 signs and houses for a birth at 06:42 IST on 14 August 1994 in Ahmedabad. The Rasi degrees that produce them are not shown there, so here is the same engine output with the working visible.

Read down the Rasi column and then the D4 column and the regrouping is plain. In the Rasi chart the Moon, Jupiter and Rahu all sit in Libra, in house 3. In D4 Jupiter leaves them: it is in the second quarter of Libra and goes to Capricorn, while the Moon and Rahu, both past 22°30', go to Cancer. Jupiter instead picks up Ketu, which arrives in Capricorn from the fourth quarter of Aries. The Sun and Mercury travel together because both are in the last quarter of Cancer. Saturn, in the 7th house of the Rasi chart, lands on the D4 Lagna. You can see the Rasi side of this for your own birth on the birth chart calculator.

Run the three self-tests from the table section on this output. Leo is fixed and stays Leo. Cancer and Libra are movable and their points go to Aries, Cancer and Capricorn, all movable. Gemini and Virgo are dual and go to Gemini and Sagittarius. Aquarius is fixed and goes to Leo. Nothing crosses a group, as the rule requires.

How to read each part of the result

The D4 sign of a graha

This is the one field that every later use depends on. On its own it tells you two things: which quarter of its Rasi sign the graha occupies, and therefore which sign lord BPHS Ch. 6 Sl. 9 assigns to that quarter. The sample's Venus in D4 Sagittarius is a statement that Venus is between 7°30' and 15° of Virgo and that the quarter is Jupiter's, because Sagittarius is Jupiter's sign. It is not a second position in the sky. A varga places a graha in a sign and gives it no degree there, a limit the engine states in its own comments and respects elsewhere.

The D4 Lagna and the twelve houses

The houses list is a whole-sign layout counted from the D4 sign of the Ascendant: for the sample, Leo is house 1, Virgo 2, Libra 3, Scorpio 4 and so on to Cancer as house 12. Every house number on the page is relative to that one sign, so the houses are exactly as reliable as the D4 Lagna and no more. If you are unsure which Rasi sign was rising, start with the Lagna calculator, which reports the rising degree this page divides.

The house number of a graha

A graha's D4 house is its D4 sign counted from the D4 Lagna. It has no fixed relation to its Rasi house. In the sample the Sun moves from house 12 to house 9, the Moon from 3 to 12, Jupiter from 3 to 6, Venus from 2 to 5 and Saturn from 7 to 1; only Mars keeps its house, 11, because both it and the Ascendant are vargottama. Two grahas that share a Rasi sign share a D4 house only if they also share a quarter.

The vargottama list

The list names every point whose D4 sign equals its Rasi sign - Ascendant and Mars in the sample. In D4 this is purely a first-quarter test, so about one point in four qualifies on average. The term is best known from Navamsa, and the page uses the same word because the shared routine applies the same equality test to every varga; a D4 match and a D9 match are different facts and should not be added together as if they were one. The list can be empty.

When the result is unavailable

If the birth time is missing or the place could not be resolved to coordinates, the handler does not cast a noon chart and guess. It returns a successful response marked as unavailable, naming what is missing. The reason is the Lagna: without it there is no house 1 and the page would have nothing honest to show in the houses column. The article on an unknown birth time sets out what still works in that case.

What BPHS says the chart is for

The use of each division is listed in BPHS Ch. 7 Sl. 1-8: the physique from Lagn, wealth from Hora, happiness through co-born from Dreshkan, fortunes from Chaturthamsa, sons and grandsons from Saptamsa, spouse from Navamsa, power and position from Dashamsa, parents from Dvadashamsa, and so on through the sixteen. For this varga the text gives one word, fortunes, and no further instruction. There is no chapter in BPHS that walks through Chaturthamsa placements one by one, and this page does not invent one.

Where, then, does the common reading for property come from? It is an association with the fourth house, and it is fair to label it as that. The kendra from which the second quarter is counted is the fourth, Bandhu Bhava, and BPHS Ch. 15 gives that house its subject matter: residential comforts in full when the house holds its own lord or the Lagna lord and is aspected by a benefic (Sl. 2), comforts from lands, conveyances and houses (Sl. 3), and fine dwellings when the tenth lord joins the fourth lord in a kendra or trine (Sl. 4). Those slokas are rules for the Rasi chart. This app's Kundali page labels its D4 card 'Fortune & property', joining the Ch. 7 word to the Ch. 15 subject. The learn page on the 4th house, Sukha Bhava covers that house in its own right.

It also helps to keep the neighbouring vargas apart. BPHS gives wealth to Hora and conveyances to Shodashamsa (D16), not to Chaturthamsa. If a D4 reading is being used to answer a question about money or vehicles, it has drifted outside the line the text draws.

Beginning, middle and end of a quarter

One more classical statement touches D4 directly. BPHS Ch. 7 Sl. 13-16 says the effects of a Hora are full, medium and nil at its beginning, middle and end, and then adds that similar applications are to be made for Dreshkan, Turyamsa, Navamsa and the rest. Turyamsa means the fourth part, which we read as this division. The engine does not implement that gradation: it reports which quarter a point is in and nothing about how far through the quarter it has travelled. If you want to apply the sloka yourself, the Rasi degree in the table above is all you need - the sample's Ascendant at 2.33° is early in a quarter that runs from 0° to 7°30', and its Saturn at 16.50° is early in one that runs from 15° to 22°30'.

A modern use: residence and settling far from home

The one book in our corpus that puts Chaturthamsa to work in case studies is the modern compilation Advanced Predictive Astrology, in its thumb rules for foreign travel. It is a recent author's working method, not a classical sloka, and is reported here as such.

• For living at a distance from the birthplace, the book looks first at the Rasi chart for a connection between the 4th lord and the 12th lord. For permanent settlement abroad it asks for the same relationship between the 4th and 12th lords to appear in the Chaturthamsa as well.
• When the 4th house of the Chaturthamsa is occupied or aspected by benefics, the book reads a decent house to live in abroad.
• When the 4th and 7th lords of the Chaturthamsa are joined in its 7th house, the book reads marriage in the foreign country after buying a house there.

Two of its case charts use the rule in the negative. In one, a native who lived abroad for years but did not settle is explained partly by the 4th and 12th lords making no relationship in either the Rasi chart or the Chaturthamsa. In another, the two lords stand in a 6-8 relationship in both charts, and the author gives that as the reason the native travelled often but did not stay. The interest for a reader is the method: the book never reads D4 alone. It checks the Rasi chart first and uses D4 as a second look at the same pair of lords.

This calculator gives you the raw material for that look and stops there. For the sample, the D4 Lagna is Leo, so the 4th house is Scorpio and its lord is Mars; the 12th house is Cancer and its lord is the Moon; the 7th house is Aquarius and its lord is Saturn. Mars is in Gemini in house 11, the Moon in Cancer in house 12, Saturn in Leo in house 1. Mars and the Moon sit in adjacent signs, neither together nor opposite. The 4th house, Scorpio, is empty. Saturn is in the 1st, not the 7th. Those are positions, and the page reports nothing beyond them: it computes no aspects in D4 and applies none of the book's rules. Whether a thumb rule from a 2000 casebook holds for a given life is a question the engine has no way to test, so it does not answer it.

Where this app reuses your D4 signs

Vimshopaka Bala: half a point out of twenty

BPHS Ch. 7 Sl. 17-25 sets out four schemes for the twenty-point strength called Vimshopaka. Chaturthamsa is absent from the first three. The Shad Varg scheme counts Rasi, Hora, Dreshkan, Navamsa, Dvadashamsa and Trimshamsa; the Sapt Varg adds Saptamsa; the Dasha Varg adds Dashamsa, Shodashamsa and Shashtiamsa. Only the full Shodasha Varg scheme of all sixteen includes the quarter division, and there it is one of the nine vargas that carry half a point each, against 3.5 for the Rasi, 3 for Navamsa and 4 for Shashtiamsa. The Vimshopaka Bala calculator uses that sixteen-varga scheme, and its weight table gives D4 exactly 0.5.

The routine takes each of the seven classical grahas, reads its dignity in its D4 sign, and awards a fraction of the half point: all of it for exaltation, three quarters for its own sign, five eighths for a friendly sign, half for a neutral sign and nothing for an enemy sign or debilitation. Rahu and Ketu are not scored because the engine keeps no dignity table for them. For the sample birth the D4 line of each breakdown is:

The table shows both what D4 contributes and how little it can move the total. The Sun is exalted in D4 and collects the full half point, yet its total is 8.69; Jupiter is debilitated in D4 and collects nothing, and the most the quarter chart could ever have added to its 6 is 0.5. A striking D4 dignity is a real fact about the chart and a small one in the sum. Friendly and enemy here are the compound relationship, which includes a temporary part read from the birth chart, so the same graha in the same D4 sign can be labelled differently in two different horoscopes.

The count of good vargas

The close of BPHS Ch. 6 describes a second way of using the divisions: counting in how many of them a graha occupies a good varga - its exaltation sign, Moolatrikona sign, own sign, or a sign owned by the lord of a kendra from the Arudha Lagna. In the sixteen-varga scheme the counts carry names, from Bhedak for two good vargas up to Sri Vallabh for all sixteen. D4 is one of the sixteen places where a graha can score. The sample's Sun (exalted in D4 Aries) and Moon (in its own sign, D4 Cancer) would each count D4 as a good varga on the first three tests. This page does not compute those named designations; it supplies the D4 sign you would need to count them.

Where D4 is not used: Shad Bala

It is easy to assume every varga feeds every strength score. It does not. BPHS Ch. 27 defines Sapt Vargaj Bal, the divisional part of positional strength, from seven vargas: Rasi, Hora, Dreshkan, Saptamsa, Navamsa, Dvadashamsa and Trimshamsa. Chaturthamsa is not among them. So a graha's D4 sign has no part in that component of Shad Bala as the text defines it, however strong or weak it looks in the quarter chart.

The Kundali page

The same computeChaturthamsa output is part of the full chart payload behind the Kundali feature, where it is drawn as a chart wheel next to the other divisional charts. There, too, it is sent only when the chart has an Ascendant; without a birth time the field is empty and no wheel is drawn from a guessed Lagna.

Birth-time sensitivity, measured

The page's limits say that the D4 Lagna changes far more often than the Rasi Lagna. To put numbers on it we ran the engine for every minute of the sample's birth date at Ahmedabad, from 00:00 to 23:59 IST.

• The D4 Lagna changed 48 times in the day, four for each of the twelve Rasi Lagnas, exactly as the table predicts.
• The shortest D4 Lagna lasted 22 minutes (20:28 to 20:50, while Aquarius was rising) and the longest 34 minutes (for example 05:58 to 06:32, while Cancer was rising). Signs do not rise at equal speed, so the windows are not equal.
• The sample's own window, D4 Lagna Leo, ran from 06:32 to 07:05. The recorded time of 06:42 is ten minutes inside it.

Now move the clock. Eleven minutes earlier, at 06:31, the Rasi Lagna is still Cancer in its last quarter and the D4 Lagna is Aries. From 07:05 the Rasi Lagna is still Leo, but in its second quarter, and the D4 Lagna is Scorpio. The grahas do not move between these three times, so their D4 signs are identical; only the numbering changes.

Notice that the three Lagnas are not neighbours. A slip across a quarter boundary moves the D4 Lagna three signs, or nine signs back to the next Rasi sign's first quarter, never one. Every graha therefore jumps three or nine houses at once: the Moon is in house 4, house 12 or house 9 depending on which side of two boundaries the birth fell. A reading built on 'the Moon in the 12th of D4' is a reading of the birth certificate's accuracy as much as of the chart.

The grahas themselves are far steadier. Across the whole sample day the Sun, Mars, Mercury, Jupiter, Venus, Saturn and the nodes each kept one D4 sign. Only the Moon changed: Aries until 03:04, Cancer from 03:04 to 15:49, then Scorpio once it entered the first quarter of the next Rasi sign. Its middle quarter lasted 12 hours 45 minutes. So a birth time that is wrong by an hour will usually leave all nine D4 signs untouched and the D4 houses wrong. The accuracy page explains how the app labels readings that depend on the birth time.

Boundaries and the ayanamsa

The other source of disagreement is the zero point. All degrees here are sidereal under the Lahiri ayanamsa, and every quarter edge sits at a multiple of 7°30' from the start of a sign. A program using a different ayanamsa, or a fuller planetary model, shifts each longitude slightly, and a point close to an edge can fall on the other side. In the sample the nearest point to an edge is Jupiter, 1.37° short of the 15° line; Mercury is 1.57° short of the end of Cancer and Saturn 1.58° past 15°. Nothing in this chart is within a degree of a boundary, so it is a robust example; your own chart may not be. The ayanamsa calculator shows the offset used for any date, and the methodology page describes how the positions are calculated.

What this page deliberately does not do

• It gives no verdict on property, land, home or fortune. BPHS supplies one word for this varga and no placement-by-placement rules, so there is nothing sourced to score.
• It computes no aspects, conjunction readings or yogas inside D4.
• It attaches no timing. A D4 placement is a fixed fact of the birth chart; dates come from the dasha and transit calculators, not from here.
• It does not apply the beginning-middle-end gradation of Ch. 7 Sl. 13-16 or report the deity of the quarter from Ch. 6 Sl. 9.
• It prescribes nothing. No remedy follows from a D4 sign in this app.

For the wider family of divisional charts, the article on Navamsa as the second chart explains how a varga relates to the Rasi chart in general, and the same reasoning applies here. The other charts BPHS Ch. 7 lists beside this one each have a page: Dashamsa (D10) for power and position, Dwadasamsa (D12) for parents, and Shashtiamsa (D60), the finest cut. All of them are listed on the calculators index.

More questions

Is Chaturthamsa the same thing as the 4th house?

No. The 4th house is one twelfth of the Rasi chart, counted from the Lagna. Chaturthamsa is a re-mapping of every point in the chart according to which quarter of its sign it occupies. The two are linked by subject in common practice, because BPHS Ch. 15 gives the 4th house lands, houses and comforts, but they are computed from different things. The 4th house page covers the house itself.

Does BPHS say D4 shows property?

The translation in our corpus says 'fortunes from Chaturthamsa' (Ch. 7 Sl. 1-8) and nothing more specific. The property reading is an association with the fourth house and is used by later authors, including the modern casebook cited above. The page's own label keeps both words: fortune and property.

Why can my Leo Ascendant only become Leo, Scorpio, Aquarius or Taurus in D4?

Because the four quarters of a sign are counted to its 1st, 4th, 7th and 10th signs, and for a fixed sign those are the four fixed signs. The same holds for every point in the chart: a movable sign maps only to movable signs and a dual sign only to dual signs. It is a quick way to catch a miscalculated chart.

Two apps give me different D4 Lagnas. Which is right?

First compare the Rasi Ascendant degree in each. If one shows the rising degree just below a multiple of 7°30' and the other just above, the difference is the ayanamsa or the planetary model, and both are internally consistent. If the degrees differ by more than a fraction, the two apps were given different times, places or time zones. In the sample, the D4 Lagna window is 33 minutes wide, so small input differences matter. See why apps disagree for the same problem in another setting.

A graha is exalted in my D4. Does that make it strong?

It adds the full half point that D4 carries in the sixteen-varga Vimshopaka score, out of twenty. In the sample the Sun is exalted in D4 and still totals 8.69. Classical strength is a sum across many divisions, weighted heavily toward the Rasi, Navamsa and Shashtiamsa; a single good D4 placement is one small term in it.

Can I see my D4 without a birth time?

Not on this page. It requires an Ascendant and reports the result as unavailable without a time and a resolved place. The D4 signs of the slower grahas do not depend on the time of day - in the sample only the Moon changed D4 sign during the whole date - but the page does not show a half-chart without houses.

Who are Sanak, Sanand, Kumar and Sanatan?

They are the four deities BPHS Ch. 6 Sl. 9 assigns to the four quarters of a sign, in that order. The text names them and gives no rule for using them, and this calculator does not output them. If you want the name for a point, its quarter number in the worked table tells you which of the four applies.

Does the D4 chart change over my life?

No. It is derived from the birth positions and is fixed. What changes over time are the dasha periods and the transits read against the birth chart, which you can follow with the Vimshottari Dasha and Gochar calculators.

Why do Rahu and Ketu get houses but no strength score?

The D4 routine treats all nine grahas alike: each has a Rasi degree, so each has a quarter, a D4 sign and a D4 house. The Vimshopaka routine is different. It needs a dignity in each varga sign, the engine keeps a dignity table only for the seven grahas from Sun to Saturn, and it leaves the nodes out rather than score them as neutral.