Synastry

Synastry (Greek σύν "together" + ἀστήρ "star") is the method of analyzing compatibility of two people by overlaying or comparing their charts / profiles.

Implementation in Different Systems

Western Astrology (#1)

Overlaying two charts. Overlaying two natal charts and analyzing inter-chart aspects (T087):

• Venus of one on Mars of the other = attraction
• Saturn on Sun = pressure and lessons

A Composite chart is also built — the average chart of the couple.

Jyotish (#18)

Kuta method. The Kuta method (गुण मिलान, Guna Milan) is a system of 36 points based on comparing the Nakshatras (T050) of the Moon. Minimum 18 points for marriage.

Other Systems

• Zi Wei (#37) — comparison of the "Palaces" of two charts
• Pythagorean Square (#46) — paired analysis of two psychomatrices
• Human Design (#13) — comparison of BodyGraphs, identifying "electromagnetic" channels

One Term — Different Procedures

A cross-system tool. The term "synastry" is one, but the procedures, criteria and ontology are fundamentally different in each system.

In Errarium. This is an example of a cross-system tool on the F1 (Diagnosis) axis with variable implementation.