Hi Ernst,
Can you explain why Me is the primary karaka in the D24 and not Ju? Isn't Ju a natural karaka planet for understanding in general?
My notion of this is Mercury's particular devotion to equanimity which engenders understanding in the sense having the most accurate point of view disregarding of any particular belief or notion of purpose, goodness or propriety. Wasn't it Mercury who demanded the truth from Tara even if it implicated him as illegitimate? So then, Mercury has the power to go beyond beliefs and obtain true understanding devoid of polarities (Mercury's neuter afterall) in the varga of the perfected knowledge, "Siddhamsa". Jupiter has great wisdom, creativity and understanding but has a tendency to takes sides with "righteousness" in one form or the other which will skew the perception some what.
Me is db in the 12th sign Pisces, whereas Ju rules it. Ju represents the Guru who embodies perfection of the Self and wisdom. A true Guru is one with God. To me, true understanding is an intuitive understanding, which is much more Jupiterian.
How I see this is that Me rules over the scientific, practical knowledge of the world in the D24. Plus you could say the higher, more Gyanic side of Me of discrimination.
Ju would be the karaka for general spiritual knowledge and wisdom in D24.
Ketu the karaka for liberation in D24.
Maybe Ernst can chime in.
From the Concrete Chart and Varga Analysis course it says this concerning D24 "Veda refers to the four classical Sanskrit texts and means “true knowledge.” This Varga thus includes not only knowledge of things in this world such as science, mathematics, etc. but more important it has to do with divine knowledge and liberation upon which one’s understanding and true knowledge become perfected. The primary Graha to be examined is Mercury."
The points you bring up are interesting with Me DB in the natural 12th house and yet the 12th bhava is the second most important factor in D24 after Me.
In the course Ernsts talks about the biggest roadblock to understanding is identifying with knowledge & the self. Getting out of the way of the truth and that Mercury's connection to Vishnu allows for the greatest understanding of everything is Vishnu.
There is a video just for the Siddamsa in the course.