Yin deficiency

Yin (阴) is the cooling, moistening, quietening half of the pair — substance, fluid, night, rest. Yang (阳) is the warming, moving, waking half. Neither is good or bad, and the tradition is not interested in more of one. It is interested in whether they hold each other in check.

That makes this pattern subtle in a way readers often miss. The heat in yin deficiency is not extra heat. It is ordinary heat with nothing left to bank it down, which is why the classics call it 虚热 xū rè, vacuity heat, and why it behaves so unlike a fever: it rises in the late afternoon, peaks at night, and is gone by morning.

The kidney (肾) holds the deep reserve, called 精 jīng, essence — the account a body draws on over a lifetime rather than over a week. Liver, heart and lung yin can run short more locally, giving dry eyes, restless nights, or a dry unproductive cough.

Level and secure, not maximal. Two thousand years of clinical writing follow from that adjective choice, and it is why the suggestions in a report for this pattern are almost all subtractions: less late, less hot, less stimulant, less noise.

Ask someone with this pattern when they feel worst and they will name a time of day. That single answer separates it from every other pattern on this list.

• Heat that builds from late afternoon and is worst in bed, without the day itself being hot.
• Warmth in the palms, the soles and the middle of the chest — the classics call it 五心烦热 wǔ xīn fán rè, vexing heat in the five centres.
• Night sweats, 盗汗 dào hàn, thief sweat: waking damp, then cooling and drying as soon as you are awake.
• A dry mouth that wants small frequent sips rather than a large glass; a dry throat at night.
• Sleep that comes fine and breaks at three or four, with heat and a fast-running mind.
• Ringing in the ears, weak or achey lower back and knees, and hair going grey early.
• Dry skin and eyes, dry stool, and flushes of heat around menopause or after a long fever.

Rest does not fix it. That is the practical separator from qi deficiency, where a good weekend genuinely helps. Here a weekend of lying down changes very little; a fortnight of being asleep before eleven changes quite a lot.

This is the most photogenic of the five patterns. The absence of coating is the sign, and it is unmistakable next to any other tongue in the file.

A tongue with no coating at all is called a mirror tongue, 镜面舌. It is the one finding in this silo that our practitioners will always mention in a report, and if it appears alongside weight loss or a long fever it is also a reason to be seen in person rather than read about.

Yin is spent by heat, by activity and above all by staying up. It is rebuilt by sleep, fluid and quiet, and the rebuilding is slower than the spending.

What tends to make it heavier

• Late nights. This is the single largest item on the page, and the tradition has said so since the Neijing.
• Alcohol, coffee, chilli, and long saunas or very hot baths late in the evening.
• Hard training in heat, and hot yoga in particular.
• Long stress without a break, which the classics describe as heat generated from constraint.
• Recovery from a high fever, and the years around menopause, when the reserve is drawn on hardest.

What tends to ease it

• Being asleep before eleven, five nights out of seven, before anything else on this list is attempted.
• Moistening food, cooked simply: pear stewed with a little rock sugar is the classic autumn dish for exactly this.
• Sipping water through the day rather than drinking a litre at once.
• Slow breathing, or ten minutes of nothing, in the hour heat usually starts.
• Moving in the morning rather than at nine at night.

The list here is cool, moist and quiet. Nothing on it is cold in the refrigerated sense; the tradition is describing the effect of the food, not its temperature.

• Pear, stewed with 银耳 yín ěr, snow fungus — the standard household dish for dryness in autumn.
• 百合 bǎi hé, dried lily bulb, simmered into congee with 莲子 lián zǐ, lotus seed.
• 枸杞 gǒu qǐ, goji, and black sesame, both associated with the kidney and liver reserve.
• 桑叶 sāng yè, mulberry leaf, and 菊花 jú huā, chrysanthemum, as a light infusion in the afternoon.
• Tofu, duck, egg, mung bean, cucumber, and white fungus soups.
• Less: chilli, lamb, ginger in quantity, and spirits.

There is a full page of these with their traditional associations under food as medicine.

The point paired with this pattern is 内关 Nèiguān, Pericardium 6, because the part of yin deficiency people most want help with is the restlessness — the chest that will not quieten, the four a.m. wakefulness, the mind running at the wrong hour. Neiguan is the confluent point of the 阴维脉 yīn wéi mài, the yin linking vessel, and its classical territory is the heart, the chest and the stomach.

Press for thirty to sixty seconds on each arm, sitting, breathing out as the pressure goes in, in the hour before bed. How to find Neiguan is written out step by step, along with the general rules for pressing.

Yin and blood are both the substantial, moistening side of the ledger, so they run short together more often than not.

• With blood deficiency it makes the commonest pair we see in women over forty: dry, pale, waking at three, periods thinning out.
• It is the opposite face of yang deficiency — one runs warm at night, the other cold all day — and a long-standing shortage of either can eventually pull the other down with it.
• It is confused with qi deficiency constantly. Both exhaust. Only one is relieved by rest.
• It sits least comfortably with dampness, and when both are named the food suggestions have to be written carefully, because what moistens one aggravates the other.

That last case is the honest argument for a written reading rather than a list off the internet: two patterns pulling in opposite directions need someone to decide which one leads.

Menopause, incidentally, is not on that list. It is a normal transition that this pattern describes well, and it is also the place where being seen by your own clinician and reading about the tradition sit together most comfortably.