Dear Aiyu,
Jyotish is like a very old house! Its walls have been painted and repainted and then painted over many many times with little attempts made to our knowledge in a documented manner that indicates that from time to time, older layers were sanded down enough before layering on a fresh coat of paint!
That foolish metaphor aside (and out of my system!) consider this:
Each day while hardly anything changes other than the lagna every couple of hours, less or more (depending on latitude of birth!) and with birthrates on an average being one every second or two, one may think that lot of babies are born with very similar charts. And perhaps they do! And yet on the other hand even twins that are really close in terms of genes, birth conditions etc oftentimes show up as challenges where very different personalities and lives started at moments close to one another at birth! Are these special cases, are these anomalies? Are these God's way of reminding us that we are still climbing and have ways to go before we arrive 'there'?
If you are the slice and dice kind, you would immediately go to amshas and vargas and do that even while you forget that the birth time you were working with may be wrong! Reverse engineering seems to have struck the fancy of many an astrologers these days, but in the face of the reality of collapsing buildings, bridges way before their designers and builders predicted, may indicate that engineering or accountancy may not be the most optimum paradigm to apply to explain jyotish and to human experience, which is after all a biological or bio-social phenomenon.
Hence we arrive at the less acute and even somewhat obstruse realm of personal planets a brief introductory article wriiten years ago, hereby re-submitted for your kind perusal:
http://www.boloji.com/astro/00312.htm
Lagna, simply due to its speedier nature compared to the lot slower sun and moon may seem attractive to the jyotishi/ni that is looking for varying patterns that conform to the variation prevalent in human society, may not be a bad place to begin, in my view. As long as it alone does not become the sole Sarathi and driver to the obfuscation and obliteration of the very important passenger (nativity) in the Chariot (sometimes spelled C-H-A-R-T) who ironically is the very reason why there needs to be a Sarathi, and a chariot, or even a chart (=astrology!) in the first place :-)
The *belief* about 'all' individuals being influenced by or corresponding to lagna for x years and then to moon and so on is sadly a generalization at best and an unexamined MYTH at its worst! If only life came in such neat packages -- we may all be clones already! Look around even this small forum (small compared to the nearly 7 billion diversities and individuals that exist on one planet, THIS ONE!) and marvel in the variety and remember to Thank God for That!!
Rohiniranjan
[quote="Aiyu"]Hmm... this is something I've been wondering for a while.
I've come across a lot of people advocating that it's ok for the janma lagna to be read instead in case the exact minute of birth is not known.
How accurate would reading from the janma lagna be? I've read somewhere that before the age of 32, significance from the lagna would account for 60% of results and from janma lagna 40%, after 32 its the other way round with janma lagna having more weigh on the chart due to the idea that "as a person grows older, their mind (moon) takes over as opposed to natural instincts (lagna)".
Could anyone shed a light on this? Thanks! :)[/quote]