Free tool
Compatibility calculator
Two birth moments, read against each other twice — once as Western synastry, once as the relationship between your Saju day masters. Most compatibility tools compare sun signs and stop there.
What is actually being compared
Synastry: one chart laid over the other
Synastry measures the angles between your planets and theirs. A trine between your Venus and their Moon is a different kind of ease than a square between your Mars and their Saturn is friction. Aspects to the Sun and Moon carry the most weight, which is why we allow them a wider orb.
The Saju element pairing
Saju compares the two day masters through the five element cycles. One element generates another (Wood feeds Fire), and one controls another (Wood breaks Earth). A generating pair tends to feel supportive but can run one-sided; a controlling pair sharpens both people and turns into a power struggle when nobody says so out loud.
Why a high number is not the goal
Charts with no hard aspects between them tend to describe pleasant relationships in which neither person is ever challenged. The couples who last are usually the ones with real friction and a shared willingness to talk about it. Read the aspect list, not just the score.