Parigasana: Gateway to the divine abode
Pariga means "gate latch" in sanskrit. See picture below. In Parigasana, the arms catch the foot just like the latch catches the U-hook on which the lock is placed. Likeness to the gate latch aside, this pose has a symbolic spiritual significance.
I taught this in the workshop series on "The Mythology and symbolism behind asanas" (video and slides in the link). Tomorrow is Vaikunta ekadashi. Even though there are about 11 other ekadashis (the 11th day of the waxing moon) every year, Vaikunta Ekadashi is especially noteworthy. In former days people fasted on every ekadashi. According to Shri Shri Ravi Shankar, the reason people traditionally fasted on the 11th day of the waxing moon is that eliminates the toxins so that the body is subject to less vagaries on the new moon day when many people experience pronounced disturbance including lack of sleep.
Vaikunta ekadashi is a special day of the year in the hindu mythology because on this day the gates of Vaikunta, the abode of the infinite (Vishnu), are said to be swung open. Shri Shri Ravishankar defines Vaikunta as the place where there is no scarcity (Vai -without; kunta - scarcity).
Legend has it that Mura, a demon, who procures a boon from Brahma that whoever he touches will die, terrorizes the Devas (the gods) and humans. The Devas worship Vishnu and Vishnu battles Mura but is not able to defeat him. He retires to a cave and lies in his cosmic sleep (Yoganidra) . When Mura catches up and tries to kill the sleeping form of Vishnu, a female being comes out of Vishnu's body due to his yogic powers and kills Mura. She is known as Ekadashi or Narayani, the female energy of Lord Vishnu. Though his own self, he grants her a boon. She, the ever merciful asked that on this day he open the door to Vaikunta so people who are prepared (through yogic austerities like fasting) can glimpse his form and attain moksha after this life. It is said that this day is so special that fasting on this day is equivalent to fasting on all the other ekadashis together.