In his meditation, Rishi Dadichi realized the difficulty the devas were facing and the boon that Vritra had acquired. He decided to give up his life to protect the devas and told Vishwakarma, the divine architect, to make a weapon out of his spine once he cast off his body. Indra uses the weapon created to kill Vritra. Vritra's boon did not protect him because the weapon was made of bone. The weapon was thence called Vajra Ayudha, because it was as strong as a diamond.

5) Tips to make the Vajrasana series of asanas easier

Vajrasana is itself easy because it is a meditation posture. The other two asanas in this series feature in the Ashtanga Yoga second series of asanas called Nadi Shodhana (purification of the nadis, through which the prana is supposed to flow). Laghu Vajrasana and Supta Vajrasana are part of a series of backbends and feature before and after Kapotasana, a challenging asana, respectively. Backbends are generally difficult (Ref: The psychology of backbends) and activate the sympathetic nervous system. The difficulty with these two backbends is in coming up.

The trick to coming up in Laghu Vajrasana is to use the Bandha. From these three articles, "Bandhas demystified", "Bandha: the great protector" and "Short and Taut vs long and loose", Bandhas are engaged when the body is taut (no loose flapping body parts) so that the prana is directed in a certain direction. That is why in Ashtanga yoga, there is emphasis on holding the arms straight (See picture above) in Laghu Vajrasana. The ideal pose requires grabbing on to the leg just above one's ankles as shown above, but body proportions vary. The more important aspect is to keep the arms straight so that the bandhas are engaged all through the body and there is a sense of integrity without loose flapping parts.

The recommended way to come up from Supta Vajrasana as taught by Ashtanga yoga teachers is to make the baddha padmasana (bound lotus pose) compact by drawing the kness toward each other. Most people need at least a little external weight to keep the knees down. The compact baddha padmasana engages Moola bandha which helps one to come up. In addition, I found a technique for coming up in Supta Vajrasana which works well for me. In fact, making this backbend, actually has become very joyful and energizing by using a mudra. This is done by pressing the heel (either one or both if your hips are very open) in the area around the groin. This becomes a Mudra. When one presses this way, one will find oneself coming up effortlessly. I confirmed with a early student of Pattabhi Jois who is also a Ashtanga vinyasa teacher in India that the groin area is indeed a sensitive spot which when pressed shoots up energy through the body.