History and origin
ISKCON, the International Society for Krishna Consciousness, was founded in New York in 1966 by A. C. Bhaktivedanta Swami Prabhupada. It belongs to the Gaudiya Vaishnava tradition that looks back to Chaitanya in sixteenth-century Bengal: devotion to Krishna, the public Hare Krishna mantra, study of the Bhagavad Gita and the Bhagavata Purana, vegetarian food and service. It is bhakti lived as a religion, with temples, a dress some members wear, and a theology that is stated rather than hinted.
Posture classes happen in some temples and community programmes. They are a courtesy to the body, or a way to welcome people who arrived looking for yoga. They are not the practice. The practice is the name, sung and heard, and the day organised around worship, study and food offered as prasadam. A studio that borrows the mantra for a fitness playlist is not this society. A visitor who wants only the singing can still tell the difference between a kirtan and a theology.
Philosophy
The name of Krishna is the practice. Singing, hearing and serving organise the day more than any shape of the limbs. A yoga pose, if a temple offers one, is a small courtesy, not the path. The theology is explicit: Krishna is worshipped as the supreme person in this tradition, and the food, the books and the singing belong to that worship. A guest can listen without pretending to believe. Pretending is a worse manners than a quiet no.
How a class proceeds
At a temple programme you will likely meet kirtan, the Hare Krishna mantra sung with drums and hand cymbals, a talk or a reading, and perhaps a simple seated or standing stretch. You are in a religious room. Participate as a guest or not at all. Shoes come off. Some areas have expectations about dress that a host can explain without scolding. Food, if offered as prasadam, is part of the tradition and is vegetarian.
You do not have to dance, bow, or take a book. Athletics are beside the point, and a class advertised as yoga inside a temple should still be read as an introduction to this life, not as a vinyasa studio that happens to have incense. Children are sometimes present. The hour is public. Leave when you have heard what you came to hear. Staying for the meal is optional, and so is the conversation afterwards.
Intensity
Physical intensity is the lowest on this scale. You may stand and sway while singing, or sit on the floor, and that is the muscular work. There is no heat, no inversion and no timed hold. People who cannot sit on the floor can use a chair at the side. The voice and the feet do more than the arms. If a separate posture class is offered, its intensity belongs to that class, not to the kirtan. This page rates the religious hour, which a tired person can attend.
Benefits
Singing a repeated line with other people can lift the breath and make an hour feel gathered rather than scattered. Hearing a text read aloud is a different kind of attention from scrolling. A shared vegetarian meal, when you want it, is ordinary hospitality inside this tradition. None of this is a fitness outcome, and none of it is a reason to join. The fair benefit for a guest is an hour of music and a clearer sense of what this religion actually does. Take that and leave the recruitment, if there is any, on the table.
Who it suits
The hour suits people drawn to Krishna bhakti, and guests who want to hear kirtan with the theology left in plain sight. It suits anyone who can be in a religious room without treating it as a costume party or a debate club. It is a confusing room if you expected a fitness studio, mirrors and a sequence.
It is the wrong room if you want the mantra stripped of Krishna, or if you are looking for a non-theistic meditation. The name is the point. It is also the wrong room if a community's enthusiasm becomes pressure to commit before you have understood the books. You can come once. Once is a complete visit.
Beside similar forms
Bhakti yoga, in the classical sense, is the wide path of devotion across many deities, poets and regions. A kirtan concert in a yoga studio may sing the same mantra and still be an event, not a temple. Siddha Yoga chants inside a different organisation and a different claim about the teacher. ISKCON is this society: Prabhupada's mission, Gaudiya Vaishnava worship, and a life of service around Krishna. The gentle stretches some temples add do not turn the hour into hatha. If the drums stop and a posture series begins, you have changed classes, and you should be told so.
Best positions
Kirtan stand
Stand with the knees soft, or sway a little, while the mantra is sung. The arms can lift if you want them to, and they can stay down. The singing is the pose. The stand keeps the breath moving and lets people who dislike sitting on the floor take part. If the crowd is dense, keep your sway inside your own feet. Sit the moment the head feels light.
Seated hearing
Sit on the floor or a chair and listen while the mantra or a reading continues. The spine is easy, not braced into a display of piety. Stillness here is respect for the sound, not an asana drill. Hearing is its own work: you follow the line instead of planning a reply. Shift when a leg sleeps. A guest who only listens has participated.
Gentle side bend
If a temple offers movement, sit or stand and lean a little to one side, the opposite arm long, for two breaths. Change sides. A small side bend is enough to ease the ribs after singing. Athletics are beside the point, and a deep fold would belong to another teacher. Skip it if the room is in the middle of worship and the movement would distract. The mantra does not need your stretch.
Floor seat
Sit cross-legged or with the legs to one side on a cloth, the hands in the lap, when a talk begins. Use a cushion so the knees are not the lesson. This seat is how a temple floor holds a crowd, and it asks for less from the back than a locked upright meditation pose. A chair at the side is the same seat for anyone who needs it. Respect here is attention, not a shape.
Palms together
Bring the palms lightly together at the chest only if the gesture is one you mean. It is a greeting in this room, not a pose to hold for strength. The shoulders stay down. If you do not want to make the gesture, a small nod is enough, and no gesture is also enough. The wrists should not ache. Separate the hands as soon as the moment has passed.
Quiet close
When the singing thins, sit or stand still for a few breaths before you look for your shoes. Let the ears settle. The close keeps you from walking into the street still half in the drum. You do not have to speak to anyone. If food is offered and you want it, take it as a guest. If you do not, the hour was already complete at the last line of the mantra.