This concept was not stated in Vedic Astrology. 

Let us say, your moon sign is Gemini. If as per the Gochara, when Saturn is transiting from Taurus through Cancer (that is the transit starts at one sign before your own sign and the transit ends at the completion of one sign after your own sign), it is said that you are undergoing Sadesati phase in you life now.  

As you all know that there are 12 signs, Aries through Pisces and it has 360 degrees in all. So, now we understand that, one sign has 30 degrees. 

Saturn takes 2 years and 6 months to traverse one sign. Sadesati period spans for three consecutive signs (one sign before your own sign, your own sign and one sign after your own sign: for Gemini sign, the Sadesati is reckoned when Saturn is transiting from Taurus to Cancer) and hence the total period of Sadesati is 7 years and 6 months. This is why this period of Saturn is known as Sadesati.

As per the Gochara prediction, Saturn in the 12th house, 1st house and in the 2nd house from your own sign is very malignant. 

How to count this position?

Let us say Saturn is transiting Leo now. So, counting anti-clockwise from Leo, the 12th house is Cancer, the 1st house is Leo and the second house is Virgo.  It means that, when Saturn is transiting the sign Leo, all the three signs such as Cancer, Leo and Virgo will have Sadesati.

Is Sadesati period very ferocious?

Saturn is usually treated to be a ferocious planet. But this concept is not correct. The positioning of Saturn is not malignant. Its aspect is malignant only. Again Saturn is a planet which believes in discipline. Any person who is not disciplined in nature will face the pangs of a malignant Saturn.

For a native, if Saturn is a benefic, then Sadesati will not be as worse than the case when Saturn is malignant for some other native. During Sadesati, one has to be very practical and plan all his works in the proper perspectives. He should avoid all negative attitudes of life and should be truthful and trustworthy. Any person, deviating from the basic good qualities, will get the wrath of Saturn and will face troubles during the Sadesati period.

If a person’s moon is elevated (exalted or posited in its own house or is in Mool Trikona), then due to his good attitude, many of the afflictions due to Sadesati will be greatly assuaged.

The best way to avoid the bad aspects of Sadesati is to cultivate the following attributes:

1. Trustworthiness

2. Sincerity

3. Respect for others

4. Team work

5. Well planned activities

6. Adaptation

7. Treating praise and disparage as one and the same.

God Bless You!

Om Shantih!    Om Shantih!!    Om Shantih!!!