accordingly if you have rahu is in 1st and ketu is in 7th and all the other plnets of the horoscope are in between rahu and ketu the kaal sarp dosh is formed.so kaal sarp dosh is formed then again according to situation of rahu and ketu it is of 12type . 1.anant kaal sarp dosh:rahu is in 1st and ketu is in 7th. 2kulik kaal sarp dosh :rahu is in 2nd and ketu is in 8th. 3.vasuki:same3rd and 9th. 4.shankhpal 5.padam. 6.mahapadam. 7.takshak. 8.karkotak. 9.shankchurn. 10.paatak. 11.vishakt. 12.shesnaag. a