वज्रासन
Vajrasana — the Thunderbolt Seat
vajra = thunderbolt, Indra's weapon — the diamond-firm seat
Kneel back on the heels — the seat of stillness traditionally sat in after meals.
In the simplest words
Kneel down and sit back on your heels, like sitting on a little chair made of your own feet. Back straight, hands on your thighs — this is how many people sit to pray or eat.
What it is
In vajrasana you kneel and sit back on the heels, spine rising straight from that firm base — the "thunderbolt" is the unshakeable quality of the seat. It is the one classical asana traditionally welcomed right after meals, and the seat of choice for kapalbhati and much japa. Ankles and knees need a little time to make friends with it; a cushion between heels and hips makes the introduction gentle.
Before you practise — health first
Skip with knee or ankle injury; sharp knee pain is a stop signal, not something to sit through. Legs falling asleep means come out and stretch.
Getting into it
Kneel with the knees together, big toes touching behind, heels apart.
Sit back into the cradle of the heels.
Rest the palms on the thighs; grow the spine tall.
If ankles or knees complain, place a cushion under them or between heels and hips.
Come out by leaning forward onto the hands and stretching the legs.
The breath
Natural breath; after meals, keep it soft and unforced.
What it is kept for
A firm japa and pranayama seat; traditionally sat in after meals for digestion.