EASY POSE (or Sukasana): Cross the legs comfortably at the ankles or both feet on the floor, pressing the lower spine forward to keep the back straight.

PERFECT POSE (Or Siddhasana): Right heel presses against the perineum, sole against left thigh. Left heel is placed an top of the right heel and presses the body above the genitals with the toes tucked into the groove between the right calf and thigh. Knees should be on the ground with heels one directly above the other. This is the most comfortable asana for many and is believed to promote psychic power.

LOTUS (or Padmasana): Lift left foot onto upper right thigh, then place right foot on left thigh as close to the body as possible, This locked-in posture is easier to do than it looks and it enhances deep meditation. The right leg is always on top.

CELIBATE (or Hero Pose): With feet hip width apart, kneel and sit between the feet. This posture channels sexual energy up the spine. If you sit in a chair, be sure that both feet are flat and evenly placed on the ground, and keep the spine straight by sitting on the sit bones.

ROCK POSE (or Vajrasana): Kneel and sit on heels (tops of feet on the ground) so that they press the nerves in the center of the buttocks. (It is named "Rock Pose" because it is said that its effect on the digestive system enables one to digest rocks).

Credits for images: www.kundaliniyoga.org taken from the best-selling book - "Transitions to a Heart Centered World" Gururattan K. Khalsa Ph.D. http://www.yogatech.com

Asana

Posture is steadily easy.
II-46: Rama Prasada

Posture is to be firm and pleasant.
II-46: Shankara

Posture should be steady and comfortable.
II-46: Osho

Posture should be steady and comfortable.
II-46: Bon Giovanni

Right poise must be firm and without strain.
II-46: Charles Johnson

Asana is defined as stability of ease.
II-46: Master E.K.

Asana

"In Patanjali's Yoga, Asana does not mean a specific posture, but means sitting. It means, mainly, sitting for meditation. Asana means a meditative seat. The way in which you sit for meditation should be such that the body is motionless and steady, and also, it should not cause any discomfort to the body; otherwise, it cannot be maintained for a long time. It is only when the posture is comfortable that you can maintain it for a long life. Maintaining the Asana for a long time is of paramount importance to facilitate proper meditation. The whole science of Yoga is only to prepare the person for meditation physically, vitally and mentally. So, a comfortable posture is a very important thing. The factor of comfort is very important. This is emphasised by the very terse definition of "Asana" in Patanjali's Yoga, namely, "Sthira Sukham Asanam". Therefore, Asana in Raja Yoga does not imply the different postures of the science of Hatha Yoga."

Sri Swami Chidananda The Philosophy, the Psychology, and Practice of Yoga
http://www.SivanandaDlshq.org/

"Asana is the third rung in the ladder of the practice of Yoga. If the Yamas and Niyamas are the foundation of Yoga, Asana may be regarded as its threshold. 'Asana', literally, means a seat. Here 'seat' does not mean a cushion or some such thing that is spread on the ground. Asana is a pose of the body or the posture which it assumes at the commencement of the practice. It is called a 'seat', because it is a posture of sitting and not standing."

"The Asana should be firm and easy. It should be steady and not cause discomfort of any kind. It should not make the student conscious of the body through tightness, tension, etc. It should be a normal posture in which he can sit for a long time."

"The Asana should be effortless. There should be no effort not only in the body but also in the mind. Absolute ease of relaxation is the sign of perfected Asana. The student should be in a most natural condition in which he is not conscious even of his breathing."

"When this bodily control is achieved, there comes freedom from the onslaught of what are called the 'pairs of opposites', such as heat and cold, hunger and thirst, joy and grief, and so on."

"Yoga is rhythm. Asana is therefore the beginning of Yoga, wherein one starts relating oneself to the cosmic order."

Sri Swami Krishnananda The Yoga System
http://www.SivanandaDlshq.org/

"(Postures) such as the Lotus, the Auspicious, the Hero, the Svastika, the Staff , the Support, the Throne, the Curlew, the Elephant, the Camel, the Confirmed, The Favourite, and others."

Trevor Leggett Shankara on the Yoga Sutras
Sankara on the Yoga Sutras (A Full Translation of the Newly Discovered Text)

"Of these, posture is steadily easy. Thus, for example, the Padmasana, the Virasana, the Bhadrasana, the Svastika, the Dandasana, .... and such others."

Rama Prasada Patanjali's Yoga Sutras
Patanjali's Yoga Sutras

j. krishnamurti