(Following is presented as a general information item only)
According to a certain esoteric tradition (which accepts the concepts of karma and reincarnation to the "earth plane") the following technique can be applied to astrologically delineate the factors of the most recent previous incarnation.
+obtain the current natal chart
+put this natal chart into an Equal House (or-my addition-into a Whole Sign) chart format
+the object is to convert this current natal chart into the Past Life Chart (PLC)
Method
a) find the cusp(sensitive point in whole sign: abbreviated sp) of the 12th house in the natal chart.
b) find the degree of the Dragon's Tail (DT; aka South Node) in the natal chart
c) add the longitudinal degrees of the natal 12th house to the longitudinal degrees of the DT: enter the result as the cusp/sp of the 1st house in the PLC
(explanation: sounds more difficult than it is: really only simple arithmetic; the zodiac wheel is reduced to 360 degrees, and handled similar to finding Arabic Parts: you take the number associated with the degree of the 12th natal house and add it to the number associated with the degree of the DT; zodiacal degree numbers may be determined from the following little table:
Aries = 0
Taurus = 30
Gemini = 60
Cancer = 90
Leo = 120
Virgo = 150
Libra = 180
Scorpio = 210
Sagittarius = 240
Capricorn = 270
Aquarius = 300
Pisces = 330
Thus, for example, 10 degrees Aries = 10; 20 degrees Capricorn = 290;
29 degrees Pisces = 359, etc etc
If the added together numbers of the natal 12th house and the natal DT exceed 360, then subtract the 360 degree circle of the zodiac from the sum and this will give you your answer:
For example:
natal 12th = 15 degrees Libra
natal DT = 29 degrees Pisces
Your total in this case would be 554 (thus exceeds 360 degree limit of the zodiac); so, subtract the circle of the zodiac-360-from this number, which leaves 194. Looking 194 up in the above table, we find this number corresponds with 14 degrees Libra: this would be entered into the PLC as the cusp/sp of the 1st PLC house)
d) once the cusp/sp of the 1st PLC house has been entered, carry that degree around for each of the other PLC houses:
Example:
PLC cusp/sp of 1st house = 14 Libra
so, cusp/sp of 2nd PLC house = 14 Scorpio; of 3rd PLC house = 14 Sagittarius; of 4th PLC house = 14 Capricorn; and so on, around the chart
(thus the final 12th PLC house cusp/sp would = 14 Virgo in this example)
e) now fill in the PLC signs/houses with planets converted from the natal chart:
+start with the Sun: find Sun's place in the natal chart, then subtract 30 degrees from it: this is the Sun's place in the PLC:
Example: natal Sun = 10 degrees Taurus; subtract 30 degrees from this, which = 10 degrees Aries: enter Sun 10Aries in the PLC
+ do the same with natal Moon, Mercury, Venus, Mars, Jupiter and Saturn (the outer planets or other natal chart elements are not included in this method)
+EXCEPTION to the above: in the case of any natal planet in retrograde, ADD 30 degrees to its natal position to convert it into the PLC:
Example: natal Jupiter is at 18 degrees Cancer-retrograde; add 30 degrees to Jupiter for the PLC; thus Jupiter's position in the PLC = 18 degrees Leo
+in the case of retrograde natal planets, they are also marked as retrograde in the PLC
+regarding the natal nodes, always ADD 30 degrees to both the natal nodal axis (that is advance the North Node 30 degrees to form the plc nodal axis, which means the SN would of course fall back by 1 sign in the plc)
You now have your completed Past Life Chart.
This esoteric tradition emphasizes including stars posited with 2 degrees of any PLC angle or planet or node, in the Past Life analysis. This tradition also believe that the PLC 12th house-and anything in it-describes the situation/condition of the incarnating ego during the period between physical incarnations (that is, the "other world" state of the individual prior to their current physical incarnation)
An interesting technique for those who might want to experiment with it.