Saturn is one of the strongest planets in the solar system. Its Indian name is Shani. Shani Dev is the son of Sun God. Shani Dev is worshiped on a Saturday. Fasts are specially prescribed for those who have a weak Shani in their birth chart, who have a Dahiya, Saade Saati, Mahadasha, etc., troubles. Worshiping Saturn God removes miseries and brings peace in life.
Shani Dev Vrat
Saturday is the day for worshiping Shani Dev, black sesame seeds, mustard oil, black urad dal and black cloth are what are dear to Shani Dev, therefore these are offered to him. Shani Stotra is also recited during the puja. There is a provision to visit the temples as well. Udyapan is done after 11 or 51 fasts.
Once all the grahas entered into a debate. Each one claimed to be the most powerful of all. To resolve the debate and come to a conclusion, they decided to approach the most famous king of those those times, King Vikramaditya.
King Vikramaditya was known as the king of justice. All his decisions were appreciated by all. All the planets went there and put before him the query.
King Vikramaditya ordered his servants to arrange chairs made of seven different metals. When the chairs were brought in the court, the king told all the planets to occupy one seat each. Since iron is dear to Lord Saturn, he occupied the last seat, which was made of iron.
Now the king declared that the planets had already decided for themselves by choosing their seats.
Lord Shani did not like the king's verdict and was annoyed. Shani Dev, proclaimed "Oh King! You do not know me, Surya stays in a Rashi for one month, Chandrama for two and a quarter of a month plus two more days, Mangal stays for one and a half month, Brihaspati for thirteen months and Budh and Shukra stay for one month each. But it is me who stays for a period starting from two and a half years and till seven and a half years. Listen oh King! Shri Ramchandra Ji had to go to Vanvaas because of the Saadhe Saati, seven and a half year term. It was because of Saadhe Saati that Lord Ram and his sena (army) entered the Lanka of Ravana and captured it. Now, you will have to pay for what you have done." having said this, Lord Shani left the place.
After a few years of peaceful living, the king's Saade Saati phase started. As a result, the king had to go through various difficulties, he went to the jungle and wandered there without food. He was employed as an oil seed crusher and had to do other odd jobs. Even his hands were cut off later.
Once when it was the last day of the Saadhe Saati time, he was working at the fields. Engrossed in the work, he started singing a melodious song. Since his Saadhe Saati time had now ended, his voice fell into the ears of a king's daughter. Impressed by the voice, she wanted to marry king Vikramaditya, despite his miserable condition. She did not know that the man was also a king himself.
Their marriage was organized and the king's time started taking a turn towards improvement. The king now realized that the Saturn God was really strong and therefore started observing the fasts on a Saturday.
He sought pardon from the God for his mistake and bowed before the deity. After the successful completion of the fasts, the king's good old days returned and he lived happily thereafter.