Vakrasana is a simple form of Ardha Matsyendrasana. Those unable to perform Ardha-Matsyendrasana generally prepare for the tougher posture by practicing the Vakrasana. This particular yogic pose was first expounded by Swami Kuvalayananda. Vakrasana is also called "twisted pose" because in doing so, spine is twisted. In Sanskrit the term `Vakra` means `twisted`.

Practice of Vakrasana
Step wise Vakrasana is shown below:

Sit erect, stretching the legs in front together.
Hands should be by the side, palm resting on the ground, fingers together pointing forward.
Slowly fold one leg (i.e. left) at the knee and place the sole on the ground near the knee of the right leg. The knee of the left leg should make 90 degree angle straight towards sky.
Taking the left hand towards back, place the palm on the ground straight from spine. Fingers should be together pointing backward.
Then place the right hand towards the other side of the left knee. If legs are stretched towards east then fingers of the hand will point towards north.
Now twist head and try to look at the backside.
While returning to the original position, first bring head to the original position.
Then take the right hand to its original position and then bring the left hand from the back and place it by the side of the body.
Slowly stretch out the folded leg and sit erect as in the first position. In the same way practice it from the other leg. This makes one round of Vakrasana.

Benefits of Vakrasana
Benefits of Vakrasana are:

Vakrasana cures constipation, flatulence, liver weakness and nervous weakness.
Reduces rigidity in the spine.
This is also useful for kidney and other stomach diseases.
It is a good exercise to make the spine flexible.
It is helpful in treating enlarged and congested liver and inactive kidneys.
It brings relief to hypertension and diabetic patients.
It stretches the thigh and tones the abdomen.
Massages the internal organs such as kidney, pancreas, spleen, liver and adrenal gland.
Improves mobility of the back and hips, and is a beneficial exercise for the eyes.
Helps in toning the sympathetic system by drawing a good supply of blood.
It is beneficial for the patients having stone in gall-bladder.
Flab on the lateral side of the abdomen gets reduced.

Caution while practicing Vakrasana
Things should not be done for practicing Vakrasana:

Although practicing this asana is simple, but pot bellied people may feel it difficult to place the hand to the other side of the knee. They are suggested to place the hand on the knee or keep it wherever it is, if it is not possible to place it on the ground.
Hernia and ulcer patients should avoid this asana.
Person having severe back pain should avoid this asana.
People who have recently undergone abdominal surgery should avoid this asana.