अर्ध मत्स्येन्द्रासन
Ardha Matsyendrasana — Half Spinal Twist
ardha = half; Matsyendra = lord of the fish, the first human hatha master
The spine wrings itself slowly from base to crown: the classical seated twist.
In the simplest words
Sit, put one foot over the other leg so its knee points up, then turn your whole upper body toward that knee, like slowly looking behind you to check who called. Sit tall first, then twist. Both sides, always!
What it is
Named for Matsyendranath, honoured as the first human teacher of hatha yoga after Shiva, the Adinatha (Hatha Yoga Pradipika I.1, I.4), this is the twist the tradition kept at its centre: one knee stands, the opposite elbow hooks outside it, and breath by breath the spine rotates, hips square, crown tall, each inhale lengthening, each exhale turning a little more. Twists wring the spine's small muscles awake and give the abdomen the sideways massage nothing else provides; the Hatha Yoga Pradipika prizes the full Matsyendrasana for kindling the digestive fire (I.27; I.29 in some editions), and the half form shares the claim. The rule is single: the spine grows LONG before it turns.
Before you practise: health first
Twists compress the belly: skip deep versions in pregnancy (take an open, gentle twist instead), after abdominal surgery, and with disc herniation. Turn from the spine, never crank with the arms.
Getting into it
Sit with legs long; bend the right knee and step the right foot outside the left thigh.
Fold the left leg in beside the right hip, or keep it long; both forms are widely taught.
Inhale, grow the spine tall; place the right hand behind you like a kickstand.
Exhale, turn right, hooking the left elbow outside the standing knee.
Inhale length, exhale turn, a little more each breath; unwind slowly and repeat left.
The breath
The twist advances only on the exhale; the inhale's job is height.
What it is kept for
Spinal mobility, a digestive massage, releasing the mid-back knots desks tie.