Synastry is the astrological technique of comparing two natal charts to understand the dynamics of a relationship — romantic, family, friendship, or professional. By overlaying the two charts and analyzing the aspects (angles) formed between planets in each, synastry reveals the energetic structure of how two people experience each other. It's the most diagnostic astrological tool for understanding relationship compatibility and challenges.
Two natal charts are placed in a bi-wheel format — your chart on the inside, your partner's on the outside (or vice versa). Astrologers analyze: planet-to-planet aspects (your Venus to their Mars), planet-in-house overlays (your Saturn falling in their 7th house), and the comparison of key points (Sun-Moon contacts, Venus-Mars contacts, Saturn contacts). Each of these creates specific relationship dynamics.
Synastry can show why a relationship feels electric (Venus-Mars contacts), why it feels destined (Sun-Moon contacts), why it feels burdened or restrictive (Saturn contacts), or why it feels chaotic (Uranus contacts). It cannot predict whether a relationship will last — that depends on choices — but it explains the dynamics you'll experience.
Two charts in deep synastry alignment feel inevitable to both people; two in difficult synastry feel like work even when love is present.
Synastry is descriptive, not prescriptive. It explains the energetic dynamics but doesn't tell you whether to stay or leave. Strong synastry between abusive partners doesn't justify staying. Difficult synastry between healthy partners doesn't mean leaving. Synastry is a map of the terrain — you choose how to walk it.