When Mars (Sevvai/Mangal) is placed at 1,2,4,7,8,12 from Ascending Lagna in Birth horoscope / jathaka this causes Sevvai Dosha. When the brides horoscope has Dosha it is feared that the husband/groom will suffer from Diseases, Financial debt, accidents and other mishaps. Similarly when the groom or boys horoscope has dosha the same effect will prevail. Some astrologers considers even the benefic planets like Jupier, venus and mercury gives worse effect than Mars under certain conditions and hence the importance for sevvai dosha should be decreased.
When either of the horoscope has sevvai dosha the other should also have dosha. For this reason a number persons suffer from late marriage. They don’t get a matching horoscope with dosha.
In a horoscope the 2nd 4th 7th and 8th houses are considered for family/money, mother/happiness, spouse and longevity respectively.
Mars is a natural malefic. It is responsible for blood, fire and dangerous weapons. When the malefic mar occupies these auspicious houses it is considered the good effect of these houses are spoiled.
But there are Nullification for Sevvai dosha.
For example, when mars occupies the 2nd house from ascending lagna it is considered dosha according to general rule. But according to special rule this is not a dosha for Libra and Pisces ascendants.
Similarly when mars occupies 4th house from lagna its is dosha by General rule. But for Cancer and Aquarius ascendants it is not dosha when sevvai occupies 4th house (Libra and Taurus respectively)
Similarly sevvai causes dosha when it occupies 8th house from ascendant. For Aquarius ascendant this is not a dosha when mars occupies 8th (Virgo)
When sevvai occupies 12th house this is not dosha for Cancer Ascendants.
For Libra ascendants it is not dosha when mars occupies 7th house (Aries)
For Capricorn and Taurus ascendants it is not dosha when mars occupies 7th house.
Irrespective of the house when the house is owned by sun or moon (Leo and Cancer) sevvai dosha is nullified.
When sevvai occupies any one of the moving signs (Sara rashi) Mesha, kadaka, Thulam, Makaram it is not dosha according to Special rule.
When there is dosha according to general rule, if Saturn accompanies or aspects mars, sevvai dosha is nullified.
When Jupiter aspects mars sevvai dosha is nullified.(Aspect is detailed in another article)
Some experts suggest when Vimshottari dasha for mars is finished the dosha will have no effect.