Whether it’s Tarot, geomancy, runes, or any other kind of art, I consider divination in general to be a process of three basic steps:

1. Hash out, refine, and formally ask the query.
2. Perform the divination to manipulate the symbols into a readable format.
3. Interpret the reading.

In geomancy, that second step is the whole process of developing the four Mothers and the rest of the chart from them.  After the querent and I refine the query sufficiently and settle on the final form of the question to be asked, and once I manipulate my tools (cards, dice, or whatever) to come up with the four Mother figures, I then proceed to draw out the entire geomantic chart with all the relevant information I’d need to start with.  Once that’s done, this is what my scribbling and scratching typically ends up like:

The exact process I follow to arrive at this mess of lines and symbols from which I divine the fates and facts of the world is this:

1. Draw out the four Mothers, then the Daughters, Nieces, and Court.
2. Label the terminals for the Via Puncti with the elemental glyphs above the Mothers and Daughters, where possible.
3. Draw out a simple square house chart, and populate it with the first twelve figures of the Shield Chart.
4. Count the number of odd points in the House Chart to find the Part of Spirit, and label it (I use a circle with two diagonal lines coming out of the bottom like legs, for which I can’t find a compatible Unicode glyph that looks similar enough, but Chris Brennan suggests using an uppercase Greek letter phi Φ, for which I like using the specific glyph U+233D “APL Functional Symbol Circle Style” ⌽).
5. Based on the Part of Spirit, label the coordinating house for the Part of Fortune (⊕).
6. Based on the sum of odd points from calculating the Part of Spirit, add the odd points of the Court to find the odd point sum of the Shield Chart.
7. Find the difference between the odd point sum of the Shield Chart and 64, double it, and add that to the odd point sum to find the Sum of the Chart.

You can see the different steps I took broken down by the above list fairly clearly as I did them (orange, red, green, yellow, pink, blue, cyan):

Making the Shield and House Charts is nothing special for us at this point, and I’ve discussed the Via Puncti before on my blog.  The Sum of the Chart is also fairly common knowledge, whereby you sum up all the points of the sixteen figures in the Shield Chart and compare it to 96 to determine how fast or slow the situation will resolve; again, it’s something I’ve discussed before.  Still, it might surprise you that I don’t actually calculate it directly, but base it on my calculations of the Part of Spirit (due to the mathematics of geomancy, the method works out to the same result).  Likewise, I don’t calculate the Part of Fortune directly, but also base it on the Part of Spirit.  So what gives?  What are these Parts, how are they calculated, and how are they used in geomancy?

First, let’s go with the more well-known of the two Parts, the Part of Fortune.  How do we find this indication?  From Christopher Cattan’s book The Geomancie (book III, chapter 21):

The question being made, after that we have judged by the houses, figures, angles, companions, aspects, the way of point, and by all the other sorts and manners before said, now resteth it to judge by the Part of Fortune.  The Part of Fortune figures, which afterwards ye must divide into twelve parts, and that which remaineth give unto the figures.  As if there rest two ye must give into unto the second figure, if there do remain four to the fourth figure, if there be six to the sixth figure, if there be eight to the eighth figure, if there be ten to the tenth figure, if there be twelve to the twelfth figure.  As by example, if the figure be of 72 points, or 84 or 96 or 108 points, then the part of fortune shall go into the twelfth.  But if the said points of the figure made, being divided by twelve, there do remain but two, as if there remain seventy and four where there remaineth but two, then (as before we have said) ye must give that unto the second house, and there shall be the Part of Fortune.  The which if the figure and house be good (for both the one and the other must be looked upon) you shall judge good, and if it be evil ye shall also judge evil; and so likewise shall ye do of all the other figures.  But if the figure be good, and the house ill, or contrary, the house good and the figure ill, you shall judge the said Part of Fortune to be mean.  And, to end ye may the more easier know the place where the figure falleth, which is called the Part of Fortune, ye shall mark it with this mark, 🌞, and thereafter ye shall judge all the question by the example that followeth. …

Many do use another manner to find Part of Fortune, in taking all the points as well of the twelve houses as the two Witnesses, and the Judge, which they do part by twelve (as is aforesaid) but because I have found no truth therein I will speak no more thereof.

If the mark Cattan proposes shows up as an embarrassingly incongruous sun emoji (like it does for me), then that’s just how it appears on your browser.  I’m using the Unicode character U+1F31E “Sun with Face” glyph as the closest approximation without overlapping with the usual glyph for the Sun (☉) for the symbol from the original text (fourth line, first character):

From Robert Fludd’s Fasciculus Geomanticus (book II, chapter 2):

Of the discovery of the part of fortune, and its placement in schemata.

Now the part of fortune ⊕ is to be discussed.  The part of fortune is of great importance in the view of the Geomancers just as in the view of the Astrologers, and is of great consideration: for in their view the sign of ⊕ and the steps to discover the Hyleg are chiefly considered, and through them the house, into which [the part of fortune] falls into as a result of the projection, truly seizes great life and energy by itself.  …

This part of fortune is to be considered with the utmost exactness, for if it falls into a good house and figure, it is of no small weight for bringing about judgment; if truly in an evil [house and figure], it brings about no meager impediment to judging [the schema].

Fludd then goes on to give other methods of calculating similar things “if the above method is seen to be obscure”, but the phrase “Part of Fortune” doesn’t appear, and he mostly focuses on ways of constructing entirely new charts for the purpose of a clearer judgment.

Lastly, the description of the Part of Fortune from John Michael Greer in his Art and Practice of Geomancy (chapter 6) on the Part of Fortune:

… The Part of Fortune, as the name implies, indicates a house from which the querent can expect good fortune to come in the situation.  In financial divinations it usually refers to a source of ready cash.

What about the Part of Spirit?  To start with, calling it that is my own innovation.  In the extant geomantic literature, it’s more commonly called the Index.  JMG discusses it since it appears in Fludd and Cattan, and though I’m unsure if it appears any earlier, Cattan is the one who (as far as I’m aware) introduced it (book III, chapter 18) by calling it one of the ways to find “the point of instruction”:

Another rule [to know for what intent a chart was made for] is to take all the uneven points of all the twelve figures, and give one to the first, one to the second, one to the third, and so consequently unto all the others, until that all the points be bestowed, and then if the last point remain on the first house, it signifieth thereby that the person hath desired to have that figured be made upon some of the demands which be of the first house; if it rest upon the second, it signifieth that the question or demand of the movable goods, or other things contained in the second house; and so shall you judge of the other houses where the point doth stay.  And if it do happen that the point of the intent do stay in the house of the thing demanded, or in the fifth, ye must judge according to the significations that the Judge doth show unto you; and when ye will judge by the same Judge, you must also take the uneven points of the Witness and the Judge, and bestow them amongst them; but that rule which is only by the 12 houses, is the better, more sure and certain. …

Fludd basically says the same thing (book II, chapter 3) and even with the same name in the chapter header (“De punctis instructionis…”), so I won’t translate it here.  As for JMG, he calls it the method the “projection of points”  and the resulting figure the “Index” (chapter 6):

… This can ferret out hidden factors in the chart.  Projection of points is done by counting up the number of single points in the first twelve figures of the chart, leaving the double points uncounted.  Take the total number of single points and subtract 12; if the result is more than 12, subtract 12 again, and repeat until you have a number less than 12.  If the final number is 0, this stands for the twelfth house.

The house identified by the projection of points is called the Index, and represents the hidden factor at work in the situation. …

Okay, enough reciting from resources.  Based on all the above, the methodology for finding the Part of Fortune goes like this:

1. Add up the number of all points in the twelve houses of the House Chart.
2. Divide by twelve.
3. The remainder points to the house of the Part of Fortune.  If the remainder is 0, then it points to the twelfth house.

The Part of Spirit’s method is nearly identical, except instead of counting all the points, we count just the single points.  For example, given the figure Acquisitio, if we’re counting all the points in it, we have six points, but if we’re just counting single points, then we only have two.  Thus, if (for either sum) we get 88, we divide that by 12.  That gets us 7.333…, so our remainder is 4 because 12 × (7.333… – 7) = 4; phrased another way, 88 ÷ 12 = 7 + 4/12.  Thus, we look at the fourth house for the given Part for which we’re doing a calculation.

Before continuing on with how we use these indications in geomancy, it’s probably best to talk about what a Part even is.  The Parts (also sometimes called Arabic Parts or Lots) are an old doctrine in astrology, dating back to at least the time of Ptolemy’s Tetrabiblos and seen in both Arabic and European astrological treatises since.  At least 97 were in use in the ninth century according to the Arabic astrologer Albumassar, over a hundred listed by the Italian astrologer Bonatti in his works, and more were developed since then, even in our modern era incorporating the outer planets past Saturn.   The Parts are constructed points in a horoscope based on the sums and differences of other observable points (e.g. Ascendant or Midheaven) or physical objects (e.g. planets or luminaries).  In essence, a Part is a mathematical harmonic between different astrological notes that describes certain in-depth areas in a querent’s life or situation that could, in theory, be sussed out by looking at the planets and their aspects alone, but are more explicitly specified by their corresponding Part.

For instance, if we’re looking at indications of someone’s mother, we could look at the ruler of the fourth house in a chart, or we could look at the Part of the Mother, which is calculated as follows:

Mother = Asc + Moon – Saturn

In other words, we start from the Ascendant, add the ecliptic longitude (the position in the Zodiac) of the Moon, then subtract the ecliptic longitude of Saturn.  Thus, in a horoscope where we have the Ascendant at 25° Scorpio, the Moon at 19° Gemini, and Saturn at 3° Taurus, then our calculation would look like this:

(25° Sco) + (19° Gem) – (3° Tau)
205° + 79° – 33°
251°
(11° Cap)

With those points as above, we end up with 251° on the ecliptic, which in zodiacal notation is 11° Capricorn, which is the degree of the Part of the Mother.  This is strictly a mathematical point, much like midpoints are in modern astrology, but used specifically to determine the presence, state, and effects of one’s mother (or all mothers) in a horoscope, and can then be interpreted like any other planet in the horoscope, except that they only receive aspects instead of making them.

While the technique isn’t as popular as it once was, even today many modern astrologers take note of the Part of Fortune.  From Bonatti’s Liber astronomiae (translated by Robert Zoller in The Arabic Parts in Astrology):

This part signifies the life, the body, and also its soul, its strength, fortune, substance, and profit, i.e. wealth and poverty, gold and silver, heaviness or lightness of things bought in the marketplace, praise and good reputation, and honors and recognition, good and evil, present and future, hidden and manifest, and it has signification over everything.  It serves more for rich men and magnates than for others.  Nevertheless, it signifies for every man according to the condition of each of those things.  And if this part and the luminaries are well disposed in nativities or revolutions, it will be notably good.  This part is called the part of the Moon or the ascendant of the Moon, and it signifies good fortune.

The Part of Fortune is a weird part, because it actually has two formulas to calculate it, only one of which is used depending on whether the horoscope is that of a day chart (Sun above the horizon) or a night chart (Sun below the horizon):

Day Fortune: Ascendant + Moon – Sun
Night Fortune: Ascendant + Sun – Moon

Later in Liber astronomiae, Bonatti describes the Part of Spirit, which he also calls the Part of the Sun or the Part of Things to Come, as follows:

The pars futurorum signifies the soul and the body after the pars fortunae and the quality of these, and faith, prophecy, religion, and the culture of God and secrets, cogitations, intentions, hidden things and everything which is absent, and courtesy and liberality, praise, good reputation, heat, and cold. …

In other words, if the Part of Fortune describes the material well-being (or lack thereof) of a horoscope, then the Part of Spirit describes the spiritual well-being; just as the Part of Fortune describes our connections to the world outside us, the Part of Spirit describes the connections of the world inside us.  Fittingly enough, the calculation for the Part of Spirit is the reverse of the Part of Fortune: while the Part of Spirit also uses two formulas, one for day and one for night, the formulas themselves are switched from the Part of Fortune:

Day Spirit: Ascendant + Sun – Moon
Night Spirit: Ascendant + Moon – Sun

Thus, the Part of Fortune and Part of Spirit are intimately connected by how they’re calculated; if you know the location of one, you know the location of the other.

Bringing the notion of the Part of Fortune into geomancy from astrology necessitated an obvious conceptual change in how it’s calculated; without degrees or the ability for certain things to fall among them, it would normally have been impossible to calculate any Part.  However, Cattan either invented or learned a way to find an equally-significant sign in geomancy by adapting the methods available to us in geomancy by counting the points and divvying the sum of the House Chart among the houses.  What none of the older geomancers seem to have noticed is that there’s an intimate relationship between the Part of Fortune and the Index in geomancy: if you know the location of one, you know the location of the other.

First, note that the Part of Fortune and the Index can only fall in even-numbered houses (e.g. house II, house IV, house VI, etc.) due to the mathematical intricacies of geomancy; this is true for similar reasons and with similar logic for why the Judge of a geomantic chart must always be an even figure.  (Why Cattan makes this explicit for the Part of Fortune but suggests wrongly that the Index can be in odd houses is a mystery to me; perhaps he simply didn’t anticipate that a calculation based on odd points could result in only even numbers.)  Thus, by performing the calculations of the Part of Fortune and Index, we can get only one of six numerical results: 2, 4, 6, 8, 10, and 0 (with 0 signifying that the sum in the calculation was evenly divisible by 12, and thus indicates the twelfth house).

After many charts of calculating the Part of Fortune and Index separately, I noticed a pattern emerging: the sums of the two separate calculations for the Part of Fortune and Index always add up to 12 (2 + 10, 4 + 8, 6 + 6, 8 + 4, or 10 + 2) or 24 (12 + 12).  Thus, if the Part of Fortune were in the eighth house, then because 12 – 8 = 4, I knew immediately that the Index would be in the fourth house; if the Index were in the sixth house, then the Part of Fortune would also need to be in the sixth house; if either indication was in the twelfth house, so would the other indication.  Again, if you know the location of one, you know the location of the other.

The mathematics behind this relationship can be described like this: if there are four rows in each figure and we’re looking at a collection of twelve figures, then there are 4 × 12 = 48 total rows.  Each row must be odd or even, and the number of odd rows plus the number of even rows must equal 48.  Plus, we know that since the houses of the Part of Fortune and Part of Spirit must both add up to 12 or 24, both of which are evenly divisible by 12, then we know that the sum of all the odd points plus all the points total must also be evenly divisible by 12.  We can check this mathematically as follows.  First, in mathematical notation, let us use the % sign to represent the modulo function, which is “the remainder after dividing by a number”.  Thus,

x = number of odd rows in the House Chart
x = number of points in the odd rows of the House Chart
x % 12 = remainder of x divided by 12 = Part of Spirit

y = number of even rows in the House Chart
y + x = 48
y = 48 – x

2y = number of points in the even rows of the House Chart
2y + x = number of all points in the House Chart
2 × (48 – x) + x
96 – 2x + x
96 – x
(96 – x) % 12 = Part of Fortune

((2y + x) + x) % 12
(96 – 2x + x + x) % 12
96 % 12
0
Q.E.D.

It was this interesting relationship between these two indications that reminded me of the relationship between the astrological Parts of Fortune and Spirit, and thus what led me to start calling the Index the Part of Spirit and reanalyzing it in that light.  Even though there’s a huge difference between how the astrologers calculate these two Parts in astrology versus how we would in geomancy and where they might be found in their separate House Charts, I find that the relationship between them is identical and, for that purpose, hugely useful in geomantic interpretation.

To briefly describe my own personal view of these Parts based on all the foregoing, the geomantic Part of Fortune indicates the source, manner, and condition of the material life of the querent: bodily health, material wealth, worldly means, and so forth.  Likewise, the geomantic Part of Spirit indicates the same but for the spiritual life of the querent: mental and spiritual well-being, divine gifts, aid from spirits or gods, and so on.  I also read notions of resources and capabilities for the querent (to answer “what can I count on to accomplish it?”) in the Part of Fortune and notions of fate and destiny of the querent (“what should I be focusing on or having faith in?”) into the Part of Spirit.

Going beyond the basic interpretation of the Parts themselves, I’ve also found a trend in charts when the two Parts are both in the sixth house or both in the twelfth house:

• If the Part of Fortune and Part of Spirit are both in house VI, then the matter is completely in the hands of the querent.  The querent has the ultimate say and ability to determine how the situation will proceed, and can change the reality of it as they need to depending on the course of action they take.  Their actions or lack thereof will be the crucial determiner in whether and how the situation will proceed.
• If the Part of Fortune and Part of Spirit are both in house XII, then the matter is completely out of the querent’s hands.  All the querent can do in the situation is react accordingly and adjust their conceptions and perceptions of the situation, because the reality of the situation will proceed without their input regardless of their attempts.  No matter what the querent might attempt, the situation will continue unfolding as it will.

Also, as one other use, I often use the Part of Spirit in readings about magical, occult, or divine ritual for the sake of figuring out what particular courses of action might be best, or determining what path one ought to take, whether in a specific ritual or in a general direction.  It’s a small extra thing, but for a practicing magician like myself who consults with and is consulted by other magicians, it’s a useful thing to know.  I touched on this very briefly in my old post on geomancy and magic, but now the reasoning behind it all becomes clear.

All that said, remember that the Parts can only fall in even-numbered houses.  In a sense, this is similar to the idea that figures that are even can be considered objective because only even figures can be Judges (as I wrote at length before).  In this case, the even-numbered houses deal with, in order: material goods, land and family, health and servants, death and spirits, work and office, mystery and restriction.  We exclude the odd-numbered houses, which deal with: the querent themselves, communication, creation/procreation/recreation, relationships and rivalries, religion and faith, friendships and patronage.  There’s a similar “inherent to my personal life and relationships” versus “external to my personal life and relationships” difference between the even and odd houses as there is between the objective versus subjective qualities between the even and odd figures.  It is because these things are more external to us that they can be things pointed to help us or focus on, because they’re things that we’re not necessarily in full control or knowledge of.

As a side note, I only read the Parts in a radical (unrotated) chart.  When the chart is rotated for a third-party reading, I don’t bother looking at or interpreting the Parts of Fortune and Spirit, because they’re house-based calculations and not figure-based, so they don’t get rotated with the chart and (to my mind) have no importance or meaning in such a rotated chart.  I find that the Parts work best (if at all) when applied to the querent themselves in a situation, and I haven’t found it useful to rotate the Parts with the rest of the chart for a third party.

Similarly, I don’t swap my calculations of the Parts of Fortune and Spirit around based on whether it’s daytime or nighttime, because the notion of a diurnal or nocturnal geomantic chart doesn’t make sense; after all, a solar figure might never even appear in a given chart, or it might appear both above and below the horizon in a geomantic House Chart.  Instead, it makes more sense for the Part of Spirit to only rely on odd points (the points that represent active elements, excised and above the world of passive matter) and the Part of Fortune to rely on both odd and even points (the co-mingling of active Spirit and passive Matter that results in the world around us).

Further, although there are over a hundred possible Arabic Parts (depending on tradition, era, and author you’re looking at), I’m disinclined to say that there are more than these two Parts in geomancy.  After all, the logic for the Parts in astrology is easily extensible, but in geomancy we’re far more limited based on the techniques and tools that we use, but at the same time, we have other techniques that can fill in just as easily (such as adding the figures of two houses together, the triads in the Shield Chart, and so forth).  That we call them “Parts” in geomancy is more due to conceptual parallel in what they mean more than how they’re calculated than anything else.

The only other way I can think of to extend the technique of geomantic Parts would be to calculate a new Part based on tallying only the even points in a House Chart and taking the remainder after dividing by 12, which could be worth exploring, but I’m unsure what it might indicate; perhaps using my own tripartite view of the world, if the Part of Spirit (odd points only) indicates the influence of the spiritual Cosmos and the Part of Fortune (odd and even points) indicates the influence of the humane World, then this third unnamed Part (even points only) might indicate the influence of the material Universe.  Who knows?  It might show something of good use in divination, if a pattern can be detected.

Ah, and one final thing, just to finish off the intro to the post regarding the Sum of the Chart.  Instead of tallying up all the individual points of the 16 figures in the Shield Chart, I take a shortcut method: find the odd sum of the chart (odd sum of the House Chart, already calculated for the Part of Spirit, plus the number of odd rows in the four Court figures), find the difference between that and 64, double it, and add it to the odd sum to come up with the total Sum of the Chart.  The reason why this works is much like some of the logic in why the Parts of Fortune and Spirit have to add up to 12 or 24: because each figure has four rows and there are 16 figures, then there are 4 × 16 = 64 total rows of points in the Shield Chart.  Since every row must be even or odd, the number of odd rows added to the number of even rows must add to 64.  Since it’s easiest to find the number of odd rows in the chart after we calculate the Part of Spirit (we just need to take into account four more figures), once we have that number we just subtract it from 64 to get the number of even rows.  Remembering that an even row has two points in it, we double that to get the number of points in the even rows, add to it the number of odd rows (which have only one point in each), and voilà, the Sum of the Chart is yours.