
Manglik or Kuja Dosha is an astrological state when the native has the planet Mars located either in the first, fourth, seventh, eight or twelfth house. This condition is identified on the basis of the norms set by the ancient texts of Vedic astrology; and is considered to be among the most feared astrological conditions especially because of its negative influence on the marital lives of the native and his or her spouse.
One can identify whether or not a native is a Manglik on the basis of studying their Kundli's or horoscope charts. The comparative analysis of the birth chart, the Navmansha and the Moon chart help determine whether or not the native is Manglik.
As previously explained, the Manglik or the Kuja Dosha is formed when the planet Mars is placed in the 1st, 4th, 7th, 8th and 12th house from the ascendant, which is also known as lagna, Chandra lagna (the moon sign) in the lagna horoscope, Chandra horoscope or Navmansha horoscope.
The worst form of this condition is considered when the planet mars is placed in the seventh house or in the ascendants. While these two placements are considered to be the most extreme, the placement of planet mars in the seventh house is believed to have the worst influence on the native and his or her spouse.
Next in severity comes the placement of the eight, fourth and twelfth houses in descending order.
A crucial loophole in the this entire system is that if a native who is a Manglik marries another native with the same astrological condition, then the negative effects of the dosha are deemed to have complimented or neutralized each other.

Mars is considered to be the most malefic and feared planets especially with respect to matters of marriage. The fierce nature of the planet and its placement in specific houses result in the Manglik or the Kuja Dosha.
Mars as a planet represents fire, electricity, weapons, aggression, chemicals, high energy, fight, accident and blood. It is because of this, that it is believed to influence the native, the spouse as well the relatives in a negative way.

The placement of planet mars influences the marital life of a Manglik couple in different ways. Let's understand how the placement of the planet in different houses impact a marriage-
Mars by nature is a hot planet and pays a significant role in our horoscopes. It is the presence of this planet that is believed to influence our actions and our ability to express emotions. From a positive perspective, it is this planet that influences the nature of a brave warrior; one who is ruthless and brave. If the planet offers a correct balance in terms of energy – it can have some very positive influences in our life.
Yet, there aren't many people who have this positive and dynamic balance and it is because of this, that this volatile planet is most feared in Vedic astrology.