This śloka continues the practical meditation instructions. The previous verses described the place, seat, and inner preparation. Now Bhagavān describes the posture of the body and the direction of the eyes.

Samaṁ kāya-śiro-grīvam dhārayan means keeping the body, head, and neck in one straight line. Here kāya refers especially to the trunk, from the hip to the neck. Śiras is the head. Grīvā is the neck. These three should be aligned.

This does not mean the body should be stiff like a wooden pole. The posture should be erect but relaxed. If the body slumps, breathing becomes uneven, dullness increases, and the mind easily slips into sleep. If the body is over-stiff, tension develops and meditation becomes a struggle. The right posture is alert, steady, and relaxed.

Acalam sthiraḥ means firm and unmoving. During meditation, the body should not keep shifting, scratching, adjusting, turning, leaning, or reacting to every small sensation. Every movement of the body gives a fresh message to the mind: “Pay attention to the body.” Therefore, external stillness helps internal steadiness.

This steadiness has to be developed gradually. Many people are not used to sitting still. A person may be able to work for hours in a chair, but sitting quietly for even ten minutes may feel difficult. Therefore, āsana is also a training. The point is not to force the body painfully, but to train it patiently so that it can remain available for meditation.

The posture also supports breathing. When the trunk, neck, and head are aligned, the breathing becomes smoother. When breathing becomes smooth, the mind is more likely to become smooth. Body, breath, and mind influence one another. A collapsed posture often supports dullness. A restless posture supports restlessness. A balanced posture supports alert quietness.

Then Bhagavān says samprekṣya nāsikāgraṁ svam — looking, as it were, at the tip of one’s own nose. This should not be misunderstood as a painful physical exercise of crossing the eyes and staring at the nose-tip. The point is that the eyes should not roam. The gaze is gently withdrawn. The eyes may be half-closed or softly settled; the sense of sight is not sent outward to explore the world.

The next phrase confirms this: diśaś ca anavalokayan — not looking around in different directions. The eyes are among the most powerful channels of distraction. If the eyes wander, the mind wanders. One small glance can bring a chain of thoughts: a person, an object, a memory, a desire, a comparison, a worry. Therefore, the meditator gives the eyes rest from outward movement.

This verse is not saying that posture alone is meditation. Meditation is the work of the mind. A person may sit perfectly straight and still be lost in thoughts. Another person may be unable to sit on the floor because of health conditions and still meditate sincerely in a chair. The posture is a support, not the essence. The essence is inner absorption. Still, for most seekers, a steady, aligned, relaxed posture is a powerful help.

Thus, 6.13 teaches physical cooperation with meditation. The body should not become an obstacle. The eyes should not become messengers of distraction. The posture should silently tell the mind: “Now we are not running outward. Now we are steady, alert, and inward.”