Buried in the Huangdi Neijing — China's oldest medical classic, around 2,000 years old — is a short line that Chinese families still act on today. It says the body has eight "hollows" (八虚, bā xū): the inner crease of both elbows, both armpits, both hip creases, and the backs of both knees. These are the body's "rooms where the gates swing" — hollow, sheltered places where the classic says residual tension and external pathogens tend to settle, and where the great meridians pass close to the surface.
The traditional habit is simple: tap each hollow gently with a hollow palm, a few minutes, a few times a week. No needles, no tools, no cost. This page shows you exactly where each hollow is, how to tap, how many taps, and — just as important — who should not do this.
The Method (Same for Every Hollow)
- Hand shape: cup your palm into a shallow bowl — fingers together and slightly bent, center of the palm hollow. Tapping with a hollow palm makes a popping sound and spreads the force instead of slapping flat skin.
- Force: light to medium. Aim for "comfortably warm," like a firm pat on a child's back. The skin may turn faintly pink — that's normal surface circulation. Bruising is not a goal and not a virtue. If a video told you dark bruising means "toxins leaving," skip that video.
- Count: start with 9 taps per hollow for the first week. If all feels fine, build to 18, and later 36. Odd numbers are the traditional counting habit, not magic.
- Rhythm: about one to two taps per second, steady like a slow drum.
- When: evening is the classic time — after a warm shower is ideal. Leave an hour after a full meal.
1 & 2. The Inner Elbows (两肘窝)
Find it: bend one elbow fully and look at the crease side — the soft triangular hollow in the inner elbow. That's it.
Tradition: the Lung, Heart, and Pericardium meridians travel this region; the classic line says "when the lung and heart harbor evil, it lingers in the two elbows." Practitioners traditionally use gentle tapping here for chest and upper-body tension and a general sense of release.
How: straighten the arm, palm up, support it with your other hand, and tap the hollow with your cupped palm — 9 to 18 taps per elbow, alternating arms.
3 & 4. The Armpits (两腋)
Find it: the armpit hollow itself, especially toward the front edge where the chest muscle meets the arm.
Tradition: the Liver meridian reaches the armpit — "when the liver harbors evil, it lingers in the two armpits." The Liver system is associated in TCM with the free flow of emotion, so this hollow is the classic one for irritability and that "wound-up" feeling. Modern eyes would say: you're lightly stimulating lymph-rich tissue and tight pectoral attachments. Both descriptions point at the same habit.
How: raise one arm overhead, cup the palm, and tap the armpit 9 times per side, keeping it light — the tissue here is more sensitive than the elbow.
5 & 6. The Hip Creases (两髀)
Find it: the crease where your thigh meets your lower abdomen — the front fold of the hip, on each side.
Tradition: "when the spleen harbors evil, it lingers in the two hips (髀)." The Spleen system governs digestion and dampness in TCM. Long sitting — the modern default — is exactly what traditional practice says settles stagnation here, which is why tapping the hip crease pairs so well with a desk-bound day.
How: stand or sit, cup the palm, and tap along the crease 9 times per side. Keep it below the belly line and away from the lower abdomen.
7 & 8. The Backs of the Knees (两腘窝)
Find it: the soft hollow at the back of each knee.
Tradition: "when the kidneys harbor evil, it lingers in the two knee-hollows (腘)." The Kidney system is the traditional root of vitality and lower-back strength, so this pair closes the routine.
How: stand with the knee slightly bent, one hand resting on a chair or wall for balance, and tap the hollow 9 times per knee. Keep taps light — large vessels run close to the surface here, so this hollow gets the gentlest treatment of the eight.
The Full 5-Minute Evening Routine
| Step | What to do | Time / count |
|---|---|---|
| 1. Loosen up | Shake the arms and legs loosely, like shaking water off your fingers | 30 seconds |
| 2. Elbows | Cupped-palm taps on both inner-elbow hollows | 9–18 taps each |
| 3. Armpits | Light taps, arm overhead (skip if pregnant) | 9 taps each |
| 4. Hip creases | Taps along the front fold of each hip | 9–18 taps each |
| 5. Knee hollows | Gentle taps, hand on a chair for balance | 9 taps each |
| 6. Close | Rub palms warm, rest one hand on the lower belly, three slow breaths | 30 seconds |
That's the whole practice. Twice a week is a fine starting dose; daily is traditional. It costs nothing and fits beside any evening — which is precisely why it has survived two thousand years of "I don't have time."
What You Should (and Shouldn't) Feel
- Normal: warmth, faint pinkness that fades within minutes, a loose or lighter feeling in the limbs, sometimes a tingle down the arm or leg.
- Too much: bruising, sharp pain, lasting redness. Reduce force or count — the tradition is firm that gentleness is the technique, not a weakness of it.
- Not expected: any specific medical improvement. This is a traditional self-care habit for comfort and circulation, not a treatment. Persistent pain or swelling in any of these areas belongs with a doctor, not with a tapping routine.
Who Should Skip It
- Anyone pregnant — the armpit and hip-crease hollows in particular are traditionally avoided.
- Anyone on blood thinners, with clotting disorders, or with a history of DVT.
- Broken or infected skin, rashes, or recent surgery in any hollow.
- Immediately after a full meal, after alcohol, or when running a fever.
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Get the Free 7-Day Guide →Educational content only — not medical advice, diagnosis, or treatment. Tapping routines are traditional self-care practices used to support comfort and circulation; they do not replace care from a qualified healthcare provider.