There are some distinctive differences between these two schools. Commonly known as Sihua Flying Stars (四化飞星) or Northern School, it was founded much earlier in the ancient Chinese history. Sihua Flying Stars places significant emphasis on the interconnection between Cells (palaces) to infer a matter. San He (Southern School 三合) on the other hand focuses on the stars characteristic as well as the star combinations.
As a result, one can quickly identify the differences on the first glance of their respective Zi Wei Chart (紫微命盘). Sihua Flying Stars uses 18 stars whereas San He uses 108 stars on a Chart.
Apart from this cosmetic difference, Sihua by its very nature traces the cause-effect of one event while San He gains advantage from the overview perspective. This is coined as Qi vs Xiang (Event vs Impression: 气与象).
Compared to other astrological readings, both Zi Wei lineages also suffer from their inherited shortcomings. These include the challenge in determining the true birth hour and their required level of difficulty to master the knowledge.
Let’s read an excerpt extracted from a Zi Wei book:
“These two different system emanated from ancient Chinese legend that there were two volumes of Zi Wei Dou Shu Classics kept in the Palace. While the “SanHe” volume was stolen, the “Si Hua” volume remained safely behind. To preserve the original “Si Hua” volume for his private use, the Emperor instructed his Imperial Astrologer to edit a falsified “Si Hua” version to complete the circulation of both volumes to the people. Upon the fall of the Qing Dynasty, the public discovered the existence of the original “Si Hua” classics”.
Copyright attributed to: Ng, CP. & Tham, Leonard (2009). Flying Star Zi WEi Dou Shu – Purple Star Astrology. Practitioners Handbook (With Special preview on Zi Wei Fengshui) pp: Cover, ISBN: 978-967-5168-07-9, Jan 2014