Most 'Saju compatibility' content online reduces to 'X zodiac is compatible with Y.' That's the bottom 5% of what real analysis looks at.

Full analysis:

1. Day Master union (天干合) — 5 stem-pair fusions: Jia-Ji, Yi-Geng, Bing-Xin, Ding-Ren, Wu-Gui. Strongest 'attraction' factor.

2. Day Master Five-Element relationship — Productive, Restraining, or Same.

3. Day Branch union or clash (六合/沖) — Six pair-unions bring ease; six clashes create friction.

4. Year-Branch relationship (zodiac) — Social-side rhythms; least weighted.

Free compatibility analyzer: https://tarofortune.pythonanywhere.com/en/compatibility