Vaikunta Ekadashi is the Shukla Paksha Ekadashi that occurs during the Dhanu month in the Hindu calendar (corresponding to late December - January in English calendar).
The Vaishnava (Worship of Vishnu) sect believes that 'Vaikunta Dwaram' or 'the gate to the Lord's Inner Sanctum' is opened on this day. The Margashirsha Shukla Paksha Ekadashi in the Lunar calendar is known as a 'Mokshada Ekadashi.' Special prayers, yagnas, discourses and speeches are arranged at Vishnu temples across the world on this auspicious day. The Shaiva sect observes the day as Trikoti Ekadashi, a religious observance where all the deities in the Hindu pantheon pay obeisance to Lord Sri Shiva at once.
According to the Vishnu Purana, fasting on Vaikuntha Ekadashi is equivalent to fasting on the remaining 23 Ekadashis of the (Hindu) year. However, according to Vaishnava tradition fasting is mandatory on all Ekadashi of both Shukla paksha and Krishna paksha. Fasting on Ekadashi is considered holier than any other religious observation.
Vishnu opened the gate of Vaikuntham (his abode) for two demons in spite of their being against him. They also asked for the boon that whoever listens to their story and sees the image of Vishnu coming out of the door (called Dwar), called Vaikunth Dwar, will reach Vaikunth as well. Temples all over India make a door kind of structure on this day for devotees to walk through.
According to Padma Purana, the female energy of Vishnu slayed the demon Muran and protects the 'Devas'. This happened on the eleventh day of lunar month during the sun's journey in the Dhanurrashi or Dhanu Rashi. Impressed by the act, Vishnu names her as 'Ekadashi' and gives her the boon that those who worship 'Ekadashi' on the day of her victory over Muran would reach 'Vaikunth' (His abode).
Vaikuntha Ekadashi is one of the important and auspicious days for Hindus. It is dedicated to Vishnu. It occurs in the Hindu calendar, in the month of Margashirsha (between December and January). When observed, it bestows liberation from the cycle of birth and death.
The significance of Vaikuntha Ekadashi is mentioned in the Padma Purana. The legend says that the Devas, unable to bear the tyranny of 'Muran' - a demon, approached Shiva, who directed them to Vishnu. A battle ensued between Vishnu and the demon and Vishnu realized that a new weapon was needed to slay Muran. In order to take rest and create a new weapon, Vishnu retired to a cave for the goddess named Haimavati in Bhadrikashrama. When Muran tried to slay Vishnu, who was sleeping, the female power that emerged from Vishnu burned Muran to ashes with her glance. Vishnu, who was pleased, named the goddess 'Ekadashi' and asked her to claim a boon. Ekadashi, instead, beseeched Vishnu that people who observed a fast on that day should be redeemed of their sins. Vishnu thus declared that people who observed a fast on that day and worshipped Ekadashi, would attain Vaikuntha. Thus came into being the first Ekadashi, which was a Dhanurmasa Shukla Paksha Ekadashi.
The demon Muran stands for the Rajasic and Tamasic qualities in people, attributed to lust, passion, inertia, arrogance etc. When one conquers these tendencies, one attains the purity of mind, Satva, indispensable for attaining of moksha, the liberation or realization of the self. For realizing the self as pure awareness, purity of mind is required. Fasting helps to keep at bay tendencies which could be triggered by intake of certain foods. Keeping vigil in the night is symbolic of awareness, or being watchful of the contents of the mind. When the mind is looked at, it becomes still. To abide in the stillness is to attain freedom or peace, acquired through merging of the mind with the self. This is symbolic of the mind automatically being absorbed at the sight of Vishnu after the arduous fast and vigil.
The belief that rice is prohibited, because Muran dwells in it, symbolically signifies that the eating of rice makes one feel heavy and hampers the vigil. This signifies that entertaining negative tendencies could hamper one's progress towards awareness or consciousness. Observance of the rituals on this auspicious day even without understanding their importance is beneficial. Hence the merit accrued through observing them with piety is believed to be immeasurable. In the Mahabharata, Bhagavad Gita the conversation between Krishna and Arjuna at the beginning of Kurukshetra War is said to have occurred on this day.
Vaikuntha Ekadashi fasting is an important aspect of those associated with it. People fast the whole day and keep vigil. Special prayers are offered to Vishnu and devotees engage in Japa (chanting of Vishnu's name) and Dhyana (Meditation). On 'Dashami', the previous day of the observance, devotees who take up Vaikuntha Ekadashi fasting are to take only lunch. On Ekadashi, the next day, they have to maintain a complete fast and engage in prayers and meditation of Vishnu. They are strictly prohibited from taking rice. That night, people keep vigil the whole night and visit the temple of Vishnu, mostly in the wee hours of the morning.
On this day, the Vaikuntha Dwaram or the Vaikuntha Vaasal, 'The Gates of Vaikundam' are believed to be kept open. The area encircling the sanctum is referred to Vaikuntha Vaasal and devotees throng to gain entry into the temple, to seek Vishnu.