PA-0171

Half Butterfly

Janu Sirsasana (yin)

BeginnerYin FoundationsYin

At a glance

A single-leg seated fold, one leg extended and the other heel drawn toward the groin, the torso releasing forward over the extended leg. It offers a more isolated hamstring and low back release than the two-legged Caterpillar, and it's often more accessible for a first sustained hold.

Let the fold happen from the hip, then release everything else.

Essence

Unlike the active Head-to-Knee Pose this shape resembles, there's no torso-turning technique to establish here, no active square-up before folding. The instruction is simpler: let the fold happen, then let go of everything else, allowing the passive weight of the torso to do the work over time.

Intention

To release the hamstring and low back passively over a sustained hold, folding over one extended leg.

What this pose develops

Physical

  • Passive hamstring length
  • Low back and connective tissue release
  • A different quality of flexibility than active stretching produces

Mental

  • Sustained stillness with an isolated, single-sided stretch
  • Noticing asymmetry between the two sides without needing to correct it

Teaching concepts

  • Cueing genuine passivity, letting the fold happen rather than actively reaching
  • Offering support so the spine can round and rest rather than being held in any particular shape

How to practise

  1. 1Sit with one leg extended, the other bent, heel drawn toward the groin.
  2. 2Fold forward over the extended leg, letting the spine round completely.
  3. 3Rest the hands, forearms, or forehead wherever they land, or on a support if using one.
  4. 4Settle in for three to five minutes, releasing residual tension with each exhale.
  5. 5Come out slowly, then switch sides.

Alignment exploration

Instead of searching for the “correct” position, notice:

  • Alignment is loose here. The spine rounds fully, the extended leg can be as straight or as bent as comfort allows, and the priority is a sustainable, passive resting position rather than a precise shape.

Breath

A slow, natural breath, with each exhale offering a chance to release any tension still being held.

Teacher’s eye

The tell is whether a student is actively reaching for their foot, which reintroduces the muscular effort this pose is meant to avoid. A cue to let the arms rest passively, wherever they land, often helps more than encouragement to reach further.

Student practice

Reflect after practising:

  • There's no need to reach for your foot. Let your torso rest wherever gravity settles it, and let your arms follow.
  • Notice if one side feels different from the other. That's normal, not something to fix.

Common movement strategies

Rather than mistakes, you may notice:

  • Support the torso on a bolster placed along the extended leg, allowing a full, passive rest rather than an actively held position.

Modifications

  • A bolster along the extended leg for the torso to rest on.
  • A folded blanket under the bent knee.
  • The extended leg's knee softened slightly if the hamstring is very tight.

Props

BolsterFolded blanket

Completion check

  • Roll up slowly, releasing the fold before switching to the other side.

Related poses

Prepares for

Caterpillar

Complements

Dragonfly (Straddle)

Alternatives

Bolster support

Progressions

Longer holds

Regressions

Shorter holds

Related movement concepts

Passive fold without active reachingIsolated, single-sided releaseAsymmetry as normal, not something to correct

Search tags

yinbeginnerhamstringlong-hold

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