Vimshamsa D20 Chart

What this section adds

The calculator above gives you a D20 sign for the Ascendant and each of the nine grahas, twelve houses counted from the D20 Lagna, and a list of points that keep their Rasi sign. The notes under it explain the arithmetic in two paragraphs. This section goes further: where the rule is written and what the text does and does not say about it, the twenty named deities the engine does not return, a slice-by-slice walk through the sample chart, how to read each kind of result, what D20 contributes to the sixteen-chart strength score, and how fast the D20 Lagna changes with the clock. Every number below comes from the same engine that runs the calculator.

The classical rule, and where it is written

Brihat Parashara Hora Shastra opens its sixth chapter with sixteen divisions of a sign, attributed to Brahma (Ch. 6, Sl. 2-4). Vimshamsa is the tenth name on that list, after Shodashamsa and before Chaturvimshamsa. Its rule is given in Sl. 17-21: a Vimshamsa is one twentieth of a sign, 1 degree 30 minutes each, and the count starts from Mesh (Aries) for a movable sign, from Dhanu (Sagittarius) for a fixed sign and from Simh (Leo) for a common sign. The same slokas then name twenty presiding deities for odd signs and a different twenty for even signs.

Two things about this rule are worth holding on to. First, the starting sign depends only on modality. BPHS Ch. 4, Sl. 5 says the twelve signs are movable, fixed and dual in order, so Aries, Cancer, Libra and Capricorn are movable; Taurus, Leo, Scorpio and Aquarius are fixed; Gemini, Virgo, Sagittarius and Pisces are common. There is no odd and even clause for the count, unlike the Saptamsa (D7) and the Dashamsa (D10). Odd and even matter in D20 only for the deity names. Second, the three starting signs are the three fire signs, and D20 shares that trio with two neighbours but orders it differently. The Shodashamsa (D16) (Sl. 16) and the Akshavedamsa (D45) (Sl. 31-32) give Leo to fixed signs; D20 gives fixed signs Sagittarius and hands Leo to the common signs. A chart program that reuses one modality table for all three will place every fixed-sign and common-sign point wrongly in D20, which is why the engine keeps a separate start rule for it.

The other classical texts in this app's library were searched for the Vimshamsa by name. Saravali, the Bhrigu Sutras and the modern case-study book this app draws on do not discuss it, so everything classical on this page rests on BPHS alone. The full list of texts is on the sources page.

The twenty presiding deities

BPHS Ch. 6, Sl. 17-21 attaches a name to each of the twenty parts. An odd sign (Aries, Gemini, Leo, Libra, Sagittarius, Aquarius) takes one list; an even sign (Taurus, Cancer, Virgo, Scorpio, Capricorn, Pisces) takes another. The table reproduces both, in the spelling of the translation this app uses. Note that the name Jaya appears twice in the odd list, at the third and eighteenth parts; that is how the translation prints it, and it is reproduced here without correction.

What BPHS reads from this chart, and how little it says

The use of each division is listed in BPHS Ch. 7, Sl. 1-8: the physique from the Lagna, wealth from Hora, co-born from Dreshkan, fortunes from Chaturthamsa, children from Saptamsa, spouse from Navamsa, power and position from Dashamsa, parents from Dvadashamsa, conveyances from Shodashamsa, and then the phrase that concerns this page: worship from Vimshamsa. Learning from Chaturvimshamsa and strength and weakness from Saptavimshamsa follow.

That one word is the whole of the instruction. BPHS does not give a chapter of Vimshamsa results the way it gives chapters on each bhava. It does not say which house of the D20 chart to look at, which graha stands for worship there, or what a malefic in a particular D20 sign means. Modern practice has built detailed D20 readings; they are not in this app's sources, so this page does not repeat them. What the sources do support is narrower and is laid out in the next three paragraphs.

First, the general test BPHS applies to every division. Ch. 6, Sl. 42-53 calls a division good for a graha when it falls in that graha's exaltation sign, Moolatrikona sign or own sign, or in a sign owned by the lord of a Kendra from the Arudha Lagna, and it sets aside the divisions of a graha that is combust, defeated or weak. So the first classical question to put to a D20 placement is a dignity question: is this graha, in its D20 sign, in a sign where it is strong? That is exactly the question the Vimshopaka Bala calculator asks of all sixteen charts, D20 among them.

Second, the houses BPHS itself ties to religious life in the Rasi chart. Ch. 11, Sl. 6 gives amulets and sacred spells to Putr Bhava, the 5th house, and Sl. 10 gives religion and visits to shrines to Dharm Bhava, the 9th house. Those are statements about the birth chart, not about D20. They tell you where the text itself looks for the subject, and a D20 reading that disagrees with the 5th and 9th of the Rasi chart has less under it than one that agrees.

Third, the one place where BPHS becomes specific about forms of worship uses a different division altogether. Ch. 33, Sl. 63-74 reads the 12th sign from the Karakamsa, the Navamsa sign of the Atma Karaka, and lists what grahas there are said to indicate: the Sun with Ketu, the Moon with Ketu, Venus with Ketu and so on, each with a named form of devotion. That method is built on the Navamsa (D9), not on the Vimshamsa. This app computes it separately in the 12th from Karakamsa calculator, and the article on the Ishta Devata question explains what that method can and cannot say. If the question that brought you here is which form of devotion a chart points to, that is the passage the source actually wrote; D20 is the chart the source names for worship in general and then leaves undescribed.

How the engine computes it, step by step

The calculator's handler is one line: it builds the birth chart and passes it to computeVimshamsa, which calls the shared routine computeVarga with three arguments, the chart, the number 20 and the D20 start rule. The chart itself is sidereal, on the Lahiri value shown by the ayanamsa calculator, and the model behind it is described on the methodology page. For each of the ten points the routine does this:

1. 1.Takes the point's Rasi sign and its degree within that sign.
2. 2.Sets the width of a part to 30 divided by 20, which is 1.5 degrees.
3. 3.Divides the degree by 1.5 and drops the fraction. The result runs from 0 for the first part to 19 for the last; a guard caps it at 19 so that a value at the very end of a sign cannot spill into a twenty-first part.
4. 4.Finds the starting sign from the Rasi sign's modality: Aries for movable, Sagittarius for fixed, Leo for common.
5. 5.Counts forward from the starting sign by the part number, one sign per part, wrapping after Pisces. That sign is the D20 sign.
6. 6.Compares the D20 sign with the Rasi sign and flags the point if they are the same.
7. 7.Once the Ascendant's D20 sign is known, numbers the twelve signs from it as houses 1 to 12 and gives each graha the house its D20 sign falls in.

Because twenty parts are more than twelve signs, the count goes once round the zodiac and then eight signs further. The table shows which D20 sign each part of a Rasi sign maps to. Parts 1 to 12 give one full lap from the starting sign; parts 13 to 20 repeat the first eight signs of that lap.

One consequence is that the D20 signs are not equally likely. From a movable sign, three degrees of arc lead to Aries but only a degree and a half lead to Capricorn. Across the whole zodiac the unevenness partly cancels, because each modality shortchanges a different four signs, but for any single Rasi sign it is real. It is a property of the rule in BPHS, not a quirk of this engine.

The sample chart, slice by slice

The example above the fold is a birth on 14 August 1994 at 06:42 IST in Ahmedabad. The page states the result; here is the working for every point, taken from the engine's own output for that birth. Degrees are within the Rasi sign.

Take the Ascendant. Leo is a fixed sign, so the count starts from Sagittarius. 2.33 divided by 1.5 is 1.55; dropping the fraction leaves 1, which is the second part. One sign on from Sagittarius is Capricorn. Take the Sun. Cancer is movable, so the count starts from Aries. 27.26 divided by 1.5 is 18.17, so the part number is 18, the nineteenth part. Eighteen signs on from Aries is one full lap of twelve plus six more, which lands on Libra. Take Venus. Virgo is common, so the count starts from Leo. 12.92 divided by 1.5 is 8.61, part number 8; eight signs on from Leo is Aries. You can check any row the same way with nothing more than the two tables above.

Three details in this chart illustrate things that happen in any D20. The Sun and Mercury are a little over a degree apart in Cancer and fall in the same part, so they share a D20 sign; that is ordinary for grahas within a degree and a half of each other. Mars joins them in Libra from a completely different Rasi sign and by a different starting rule, which shows that sharing a D20 sign says nothing about being close in the sky. And Venus sits at 12.92 degrees of Virgo, 0.92 of a degree past the 12-degree line and 0.58 short of the next line at 13.5; had it been at 11.99 it would be in the eighth part and in Pisces instead of Aries.

If you want the deity name for a point, use the part number in this table and the odd or even column of the deity table. The sample Ascendant is in Leo, an odd sign, in the second part, which the BPHS list labels Gauri. The sample Sun is in Cancer, an even sign, in the nineteenth part, labelled Mangal. This lookup is done by hand from the text; it is not part of the calculator's output.

How to read each kind of result

The D20 sign of a graha

Each graha's row shows a sign. The reading BPHS supports is the dignity test described earlier: compare the D20 sign with the signs where that graha is exalted, in its own sign or debilitated. In the sample, Jupiter's D20 sign is Capricorn and the Sun's is Libra, which the engine's dignity table marks as debilitation for each; no graha in the sample sits in its own or exaltation sign in D20. That is a statement about one chart out of sixteen with a small weight, as the strength section below shows. It is not a statement about a person's sincerity or faith, and the text does not make it one.

The D20 Lagna and the houses

The engine lays out twelve whole-sign houses from the D20 sign of the Ascendant and reports the house each graha occupies. BPHS defines the house groups once for all charts in Ch. 7, Sl. 33-36: Kendras are the 1st, 4th, 7th and 10th; trines are the 5th and 9th; the 6th, 8th and 12th are the Dusthanas. In the sample, Jupiter is in the 1st, Venus in the 4th and the Sun, Mars and Mercury in the 10th, all Kendras; the Moon and both nodes are in the 8th, a Dusthana; Saturn is in the 11th. You may describe a D20 chart in those terms. What you cannot do from this app's sources is attach a classical verdict to a specific D20 house, because BPHS gives none. The house numbers are also the most fragile part of the output, since all of them are counted from a Lagna that changes every few minutes; see the birth-time section before leaning on any of them. Your Rasi Ascendant itself is on the Lagna calculator.

The list of points that keep their Rasi sign

The result carries a list, empty in the sample, of points whose D20 sign equals their Rasi sign. In the engine's code this flag is named vargottama, a name shared by every division it computes. Be careful with the word. BPHS defines Vargottama in a note to Ch. 36, Sl. 38-39 as a graha occupying the same Rasi and the same Navamsa, so the classical term belongs to D9. A point that keeps its sign in D20 is a fact about the arithmetic; the sources give it no separate meaning, which is why the page text calls it a match. The table shows exactly where it can happen.

Eight signs have two such windows, three degrees in all; Gemini, Leo, Scorpio and Capricorn have one, a degree and a half. Averaged over the zodiac that is a one-in-twelve chance for any single point, so with ten points an empty list, as in the sample, and a list with one or two names are both unremarkable. The sample's Moon at Libra 24.64 shows how near a point can pass: Libra's second window opens at 27 degrees.

Rahu and Ketu

The chart model places Ketu exactly 180 degrees from Rahu, so the two always sit at the same degree of opposite signs. Opposite signs share a modality, so they share a starting sign and a part number, and therefore always share a D20 sign and a D20 house. In the sample both are in Leo in the 8th. This is a consequence of the rule, the same in every chart, and should not be read as a conjunction that is special to yours.

When no chart is returned

The calculator is gated on the Ascendant. Without a birth time, or with a place that does not resolve to coordinates, it returns a message naming what is missing instead of a chart. The same gate applies inside the full Kundali, where the D20 block is left empty when there is no Ascendant. What a missing birth time costs across the whole app is set out in the article on unknown birth times.

D20 inside the sixteen-chart strength score

BPHS does more with the divisions than assign each a topic. Ch. 7, Sl. 9-12 introduces Vimshopaka Bala, a twenty-point strength built by weighting a graha's dignity across a set of divisions, and the chapter gives four sets. The Vimshamsa is absent from the first three. The Shad Varg scheme (Sl. 17-19) uses Rasi, Hora, Dreshkan, Navamsa, Dvadashamsa and Trimshamsa; Sapt Varg adds Saptamsa; Dasha Varg (Sl. 20) adds Dashamsa, Shodashamsa and Shashtiamsa. D20 enters only in the fourth, the Shodash Varg scheme of Sl. 21-25, which gives Rasi 3.5, Shashtiamsa 4, Navamsa 3, Shodashamsa 2, one point each to Hora, Dreshkan and Trimshamsa, and half a point to each of the remaining nine divisions. Vimshamsa is one of those nine.

So in the text's own accounting, D20 is worth half a point out of twenty, one fortieth of the total, the same as D4, D7, D10, D12, D24, D27, D40 and D45. That is a useful sense of proportion. A graha that looks poor in D20 has lost at most half a point of its sixteen-chart strength, and one that looks excellent has gained at most the same.

The engine implements the Shodash Varg scheme. For each of the seven grahas from the Sun to Saturn it takes the D20 sign, asks its dignity table what the graha is in that sign, and multiplies the half-point weight by a dignity factor: full for exaltation, 0.75 for own sign, 0.625 for a friend's sign, 0.5 for a neutral sign and nothing for an enemy's sign or debilitation. Friendship is the combined natural and temporary relationship, taken from the birth chart. Moolatrikona, which is a range of degrees and not a whole sign, is tested only in the Rasi chart, because a division places a graha in a sign and not at a degree. Rahu and Ketu are left out because the dignity table gives them no signs. These are the D20 rows for the sample:

Read the fourth column against the fifth. Jupiter earns nothing from D20 and totals 6.00; had it been exalted in D20 it would total 6.50 and stay in the same band. The D20 row never decides a graha's band on its own unless the total is already within half a point of a line. The lines themselves come from Ch. 7, Sl. 26-27, which sets them at 5, 10 and 15; note that the text calls the 10 to 15 range mediocre, where the engine's label for it is good. Two more classical refinements are stated in the text and not applied by the engine: Ch. 6, Sl. 42-53 sets aside the divisions of a combust or defeated graha, and Ch. 7, Sl. 13-16 grades the effect as full, medium or nil at the beginning, middle and end of a division. The full table for your own chart is on the Vimshopaka Bala page.

Birth-time sensitivity, measured

A part is 1.5 degrees wide. The grahas cross that slowly; the Ascendant does not. To show the scale, the engine was run for the sample birth at several clock times with the date and place unchanged.

Between 06:36 and 06:54 the Ascendant moved 4.05 degrees in eighteen minutes, so on that morning at that latitude one part of D20 lasted between six and seven minutes. The sample's Capricorn Lagna holds from shortly before 06:39 to just before 06:45. Three minutes later than the recorded time and the D20 Lagna is Aquarius, with Jupiter moved from the 1st house to the 12th. Six minutes earlier and it is Sagittarius, with Jupiter in the 2nd. The speed of the Ascendant varies with the rising sign and the latitude, so the figure of six to seven minutes belongs to this example and not to every birth, but the order of magnitude holds: a D20 Lagna is a matter of minutes.

The grahas are far steadier. Across the whole hour from 06:12 to 07:12 the Moon moved from Libra 24.35 to Libra 24.93, about 0.58 of a degree, and stayed in the seventeenth part and in Leo throughout; no other graha changed its D20 sign either. At that rate the Moon needs roughly two and a half hours to cross a part, and the slower grahas need days or longer. So the two halves of the result deserve very different levels of trust. The D20 signs of the grahas survive an ordinary uncertainty in the birth time, the Moon's included unless it sits near a line. The D20 Lagna and every house number do not survive an error of a few minutes.

Limits of this calculation

• The positions come from a formula-based model, not from an observatory-grade ephemeris; the accuracy page covers what the app can and cannot be precise about. With parts only 1.5 degrees wide, a point close to a line can fall on the other side in another program. The sample has one: at 06:45 the Ascendant reads 3.00 degrees, exactly on the line between the second and third parts.
• Degrees are carried to hundredths. A hundredth of a degree is 36 arcseconds, small against a part of 90 arcminutes, but it is the resolution at which a line is decided.
• The ayanamsa is Lahiri. A program using another ayanamsa shifts every sidereal degree by the difference between the two, so its D20 signs can differ from these.
• Rahu is computed as the mean lunar node in this model, with Ketu opposite it. A program that computes the node differently can place both in a different part.
• The output is signs, houses and matches. The engine attaches no interpretation of worship, devotion or spiritual practice to them, and BPHS, the only source that names this chart, gives no detailed results for it.
• The deity names in BPHS Ch. 6, Sl. 17-21 are not computed. Looking one up by hand is a reading of the text, not an output of this tool.

Where D20 sits among the other charts

The Vimshamsa is one of sixteen, and it is read best next to its neighbours. Start from the birth chart, where the 5th and 9th houses carry the subjects BPHS ties to religious life. The Navamsa is the division the text weights most heavily after the Rasi and Shashtiamsa, and the one its worship-specific passage is built on; the Navamsa article explains why. In the BPHS list D20 stands between conveyances and learning: the Shodashamsa (D16) before it and the Chaturvimshamsa (D24) after it, followed by the Saptavimshamsa (D27) for strength and weakness. For the Jaimini approach to the same subject, the Karakamsa calculator finds the Atma Karaka's Navamsa sign that Ch. 33 reads from. And since Jupiter is the graha most readers look at first in this chart, the page on Jupiter in Vedic astrology is the place to start on that graha. All the tools are listed on the calculators index.

More questions

What does Vimshamsa mean?

It means a twentieth part. BPHS Ch. 6, Sl. 17-21 defines it as one twentieth of a sign, 1 degree 30 minutes each. D20 is the modern shorthand for the same thing.

Does the D20 chart tell me which deity to worship?

Not from the sources this app uses. BPHS Ch. 7 says only that worship is to be considered from the Vimshamsa and gives no rules for doing so. The passage that names forms of worship, Ch. 33, Sl. 63-74, uses the 12th sign from the Karakamsa in the Navamsa. That is computed on the 12th from Karakamsa page, which also states the limits of that method.

Why are there two lists of deity names?

BPHS gives one list of twenty for odd signs and another for even signs. Odd and even here mean the sign's number counted from Aries: Aries, Gemini, Leo, Libra, Sagittarius and Aquarius are odd, the rest even. The split affects only the names. The D20 sign itself is decided by modality.

Why do Rahu and Ketu always share a D20 sign?

Ketu is set 180 degrees from Rahu, so they are at the same degree of opposite signs. Opposite signs have the same modality, hence the same starting sign and the same part number, hence the same D20 sign and house. It happens in every chart.

Is a planet that keeps its sign in D20 vargottama?

The engine uses that name for the flag in every division, but BPHS defines Vargottama as the same sign in the Rasi and the Navamsa. A match in D20 is real arithmetic with no classical meaning attached in this app's sources. Each sign has one or two 1.5-degree windows where it occurs, listed in the table above.

How much does D20 count towards a planet's overall strength?

Half a point out of twenty in the sixteen-chart Vimshopaka scheme of BPHS Ch. 7, Sl. 21-25. It is not part of the six-chart, seven-chart or ten-chart schemes at all.

Another site shows a different D20 Lagna for me. Which is right?

Check three things in order: the birth time each was given, to the minute; the ayanamsa; and whether the other site starts fixed signs from Sagittarius and common signs from Leo, as BPHS Ch. 6 states. A difference of a few minutes in time, or of a fraction of a degree in ayanamsa, is enough to change a D20 Lagna.

My birth time is only approximate. Is any of this usable?

The D20 signs of the grahas usually are, because a graha takes hours or days to cross a part. The D20 Lagna and the house numbers are not, because the Ascendant crosses a part in minutes. In the sample the Lagna changed twice within six minutes of the recorded time.

Does the engine use the deity names or the beginning, middle and end grading?

No. It returns the sign, the house and the same-sign flag. The deity names of Ch. 6 and the full, medium and nil grading of Ch. 7, Sl. 13-16 are described on this page from the text and are not applied in any score.