This is highly dreaded yoga in the astrology.
We know that Rahu and Ketu are the two nodes of the Moon and the Moon denotes the abundance of all auspicious things. The deposition of all the planets between the nodes is indicative of tangled skein of the Karmic forces in the horoscope. It is generally believed that Ketu is the saturation points of the Karmic forces whereas the Rahu denotes the discharge point of Karmic vibrations. On the basis of this theory, some scholars believe that Kala-Sarpa yoga manifests only if the planets are disposed between Ketu and Rahu. If they are placed between the Rahu and Ketu this yoga is not formed. But that is not the case, as we would see in the subsequent discussions through different charts. Both Rahu and Ketu are extremely sensitive points of the horoscope and, as such, when all the planets fall between them savants considers it as a sign of impending doom. A careful study of the characteristics of Rahu and Ketu as given in various astrological texts reveal that they are the harbingers of down-fall, disappointments and intractable troubles. Hence it is quite natural to believe that nodes exercising their sway on all the planets would engender problems and frustrations. The vibration of Rahu is such that it actuates an action which is sudden and unexpected. It always seeks independence through impatience. Opposition and misunderstandings are the two principal posts on which it courts its catastrophic profundity. It relishes the estrangements and eccentricity is it favoured ground for play. The impulse of Rahu condense rapidly and skedaddle swiftly in such a speedy and consecutive pattern that there are hardly any room left for caution and damage controls. The impact of Rahu is more on the nervous system than any other planets and often broods unnecessary anxieties and discontentment. It affects destiny in a devastating way. The vibration of Ketu on the other hand is subtle and obscure causing more damage to the ego than the body. Its influences have the features of fascination and illusive magnetism towards the thing of peculiar pretensions. Instead of impelling the native towards the opportunities, it generally drives them to the formidable front of impracticalities and impossibilities. Disorganisations and complications are its inseparable attributes and it can be safely accused for gradual wastage of potentialities. Ketu always stirs the deep-seated personality of the men and prompts them to err and generate contradiction. Perversion and whimsicality are the two posts through which it masquerades its profound but superficial sensibilities. Ketu is the planet of ultimate dissatisfaction which subsists even in the event of unprecedented success. However, on spiritual plane the role of these two planets change squarely but the effects of Kala-Sarpa Yoga is not based on those imports. The Rahu and Ketu necessarily signify the union of positive and negative aspects of the Karmic attributes and contain within them immeasurable latent faculties. That is why it has been said in this aphorism that when they occupy the Nakshatra of benefics like Jupiter and Venus they reverse their role. Paucity is converted to prosperity and ignorance is replaced by knowledge. In esoteric terms, the nodes are the planets of mysterious splendour. When the dispositors of Rahu and Ketu articulate themselves through conjunction, aspect or Nakshatra disposition etc. miraculous results are always anticipated. The existence of Kala Sarpa Yoga in the horoscope indicates very strong karmic bondage of the natives. Such people are always fired by some unknown zeal and if they lack the spiritual orientation in their mental being, the sturdy impulses of this yoga can sweep away their good sense leading to indulgence in violent and catastrophic acts. Because of this fact Kala-Sarpa Yoga is feared by many but this fear is out of an exaggerated propagation of its virile effects. The invigorating impulses generated by the nodes are not always designated to savage acts. Many a times it has been found to be giving sobering placidity to the natives because of the enfeebled conditions of the planets trapped within the nodal axis. In that case the natives become intellectually numb and feel inclined towards the religiosity, albeit, their meditational and spiritual pretensions are ethical rubbish of deep seated complexes. Let us not forget the fact that Ketu like Mars is a planet of logistic configuration and Rahu is notoriously intelligent. It was the demon Swarabhana alone who could know the deceiving tactics of Vishwa Mohini (Maha Vishnu), though in the process he got himself beheaded. So the argumentative abilities and sharp logic of the persons possessing Kala-Sarpa yoga are always appreciable and if they are attitudinally positive, this yoga becomes an asset for them.