Compatibility Analysis: Vedic Astrology has a unique system of determining the compatibility between two charts. Chart compatibility is determined by precise analysis of how the planetary positions in the charts compare and interact. Traditionally, the position of the Moon is considered the most important factor, and a simply scoring system based on the Moon alone has become very popular in India. This system is called the "Koota" system, as it expresses the degree of compatibility in "kootas" (points).

What is the rationale behind a compatibility calculation? Compatibility for the purpose of love has several aspects. Each aspect has to be taken care of, but together they form an optimal situation.

Similarity: Astrologically, one can determine how much the two people have a similar basis in their psychological makeup. This similarity gives them the necessary common ground to feel comfortable about being close. Without having commonalities, love has to bridge too far of a gap to be stable and will not be able to survive. For example, in Vedic Astrology terms, the Ganam (classification of Divine, human and demon) of the Moon's Nakshatra should be the same. Also the caste of the Moon's nakshatra should be the same.

Difference: Just like 2 magnets attract each other only with the opposite poles, Vedic Astrology compatibility specifies various factors that should not be the same. If the couple is having these factors identical, some kind of over emphasis will take place, and too much of the same thing is harmful here. For example, the Rajju (one of the nakshatra classifications) of the two Moons should be different. If they are the same, negative results are predicted based on the nature of the Rajju group.

Placement: In real life, too close can be too close, and too far can be too far. In Vedic Astrology there is rich set of techniques that evaluate just how optimal the Moon's placement is relative to one another. Since specific distances (measures in the number of nakshatras) have different meanings, each carries a positive or negative compatibility rating. For example, having the Groom's nakshatra right next to the Bride's, is great, but if there is just one nakshtra in between it is considered negative.

Unique Matching: Other factors have to be uniquely rated to properly judge what any one particular quality goes well with. For example, if one of the Moon's is in Purvaphalguni (one of the nakshatras), it will work out well if the other's Moon is in Anuradha. Many specific favorable and unfavorable combinations are specified, based on unique characteristics of the factors considered.

Cultural Reinforcements: Finally, the Vedic Astrology compatibility system has an aspect that considers the favorable reinforcement of the relationship man and woman have from a biological/cultural perspective. For example, if the man's Moon is in a male Nakshatra, and the woman has the Moon in a female nakshatra, that is best, and will support their natural male-female balance.

The traditional approach in Vedic Astrology is to consider these factors for the Moon sign only. Many people extend the same principles to also compare the Ascendant's positions and the Sun's positions in thetwo charts. And finally one could superimpose the two charts entirely, and evaluate in detail how they work together.

Since the Moon is so critical to how our feelings operate, and relationships are predominantly based on feelings, there is no doubt that the Moon plays a major role. A good Moon compatibility will generallyindicate a good emotional / mental fit.

The Ascendant represents the personality of the individual, which is a more outward and public aspect of the person. A good Ascendant based compatibility is therefore favorable for having cordial public relations together. When the two Ascendants are not favorable together, the couple may have a hard time presenting themselves coherently to the world.

The Sun's position relates to our physical body and spiritual nature. Compatibility in this regard indicates being physically comfortable and spiritually aligned. A lack of compatibility indicates physical needs or characteristics that do not work well together, and spiritual values or aspirations that do not mutually support each other.

By superimposing the 2 charts, one can analyze just how the planets in one chart influence the planets and houses in the other chart. This analysis can reveal a lot of detailed information about how one person affects the other person's life. Even though this analysis can provide a rich and interesting source of predictions, it should be considered as less important than the Moon based compatibility for the purpose of predicting overall compatibility of the couple.