Why these pages sit together
Because they all answer the same question: “can this work between us?” It is by far the most common thing asked of astrology, and it is what brings most people to a page about signs — not curiosity about houses or aspects.
Sign compatibility sets out the traditional grid, the one that pairs the elements. Love sign by sign goes down to the portrait: what tradition ascribes to each sign in a couple, and how it sees them through a break-up. Biorhythms belong to another family — they look not at the sky but at a date of birth, and they can be calculated.
Three pages look at the couple with other eyes: the Moon and Venus, which describe in astrology what the Sun sign leaves out, then two traditions that have matched signs for centuries — the Chinese zodiac and its twelve animals, Vedic astrology and its 36 points.
What to know before reading
None of these approaches has demonstrated predictive value. Controlled studies of astrological compatibility have never found an effect: not on the probability of marrying, not on the probability of divorcing, including in samples of several hundred thousand couples. Biorhythms were tested in the 1970s and 1980s against accidents, athletic performance and mortality, with no result either.
That does not make these pages useless. A sign portrait is a conversation starter, and a conversation about what you expect from a relationship beats no conversation at all. That is the basis on which these pages exist, and it is written on each of them.